diff --git a/m4/moo-flags.m4 b/m4/moo-flags.m4
index 0fbe191a..c9ec7c9b 100644
--- a/m4/moo-flags.m4
+++ b/m4/moo-flags.m4
@@ -91,8 +91,9 @@ MOO_COMPILER
 
 _MOO_AC_CHECK_COMPILER_OPTIONS([dnl
 -Wall -Wextra -fexceptions -fno-strict-aliasing dnl
--Wno-missing-field-initializers -Wno-overlength-strings dnl
+-Wno-missing-field-initializers dnl
 -Wno-format-y2k -Wno-overlength-strings dnl
+-Wno-deprecated-declarations dnl
 ])
 _MOO_AC_CHECK_CXX_COMPILER_OPTIONS([dnl
 -std=c++11 -fno-rtti dnl
diff --git a/moo/medit-app/parse.h b/moo/medit-app/parse.h
index d4ee1c28..2a2684a1 100644
--- a/moo/medit-app/parse.h
+++ b/moo/medit-app/parse.h
@@ -191,7 +191,7 @@ parse_file (const char  *string,
     if (!*current_dir)
         *current_dir = g_get_current_dir ();
 
-    filename = g_build_filename (*current_dir, string, NULL);
+    filename = g_build_filename (*current_dir, string, nullptr);
     ret = parse_filename (filename);
 
     g_free (filename);
diff --git a/moo/mooapp/mooapp.cpp b/moo/mooapp/mooapp.cpp
index 0c4c374a..d2b97063 100644
--- a/moo/mooapp/mooapp.cpp
+++ b/moo/mooapp/mooapp.cpp
@@ -972,26 +972,26 @@ install_common_actions (void)
                                  "tooltip", GTK_STOCK_PREFERENCES,
                                  "stock-id", GTK_STOCK_PREFERENCES,
                                  "closure-callback", moo_app_prefs_dialog,
-                                 NULL);
+                                 nullptr);
 
     moo_window_class_new_action (klass, "About", NULL,
                                  "label", GTK_STOCK_ABOUT,
                                  "no-accel", TRUE,
                                  "stock-id", GTK_STOCK_ABOUT,
                                  "closure-callback", moo_app_about_dialog,
-                                 NULL);
+                                 nullptr);
 
     moo_window_class_new_action (klass, "Help", NULL,
                                  "label", GTK_STOCK_HELP,
                                  "default-accel", MOO_APP_ACCEL_HELP,
                                  "stock-id", GTK_STOCK_HELP,
                                  "closure-callback", moo_app_help,
-                                 NULL);
+                                 nullptr);
 
     moo_window_class_new_action (klass, "ReportBug", NULL,
                                  "label", _("Report a Bug..."),
                                  "closure-callback", moo_app_report_bug,
-                                 NULL);
+                                 nullptr);
 
     moo_window_class_new_action (klass, "Quit", NULL,
                                  "display-name", GTK_STOCK_QUIT,
@@ -1001,7 +1001,7 @@ install_common_actions (void)
                                  "default-accel", MOO_APP_ACCEL_QUIT,
                                  "closure-callback", moo_app_quit,
                                  "closure-proxy-func", moo_app_instance,
-                                 NULL);
+                                 nullptr);
 
     g_type_class_unref (klass);
 }
diff --git a/moo/mooapp/moohtml.cpp b/moo/mooapp/moohtml.cpp
index ae97053e..ef300572 100644
--- a/moo/mooapp/moohtml.cpp
+++ b/moo/mooapp/moohtml.cpp
@@ -213,7 +213,7 @@ _moo_html_tag_class_init (MooHtmlTagClass *klass)
                                      g_param_spec_string ("href",
                                              "href",
                                              "href",
-                                             NULL,
+                                             nullptr,
                                              (GParamFlags) G_PARAM_READWRITE));
 }
 
@@ -221,9 +221,9 @@ _moo_html_tag_class_init (MooHtmlTagClass *klass)
 static void
 _moo_html_tag_init (MooHtmlTag *tag)
 {
-    tag->href = NULL;
-    tag->parent = NULL;
-    tag->attr = NULL;
+    tag->href = nullptr;
+    tag->parent = nullptr;
+    tag->attr = nullptr;
 }
 
 
@@ -309,7 +309,7 @@ _moo_html_class_init (MooHtmlClass *klass)
                                      g_param_spec_string ("title",
                                              "title",
                                              "title",
-                                             NULL,
+                                             nullptr,
                                              (GParamFlags) G_PARAM_READWRITE));
 
     g_object_class_install_property (gobject_class,
@@ -317,7 +317,7 @@ _moo_html_class_init (MooHtmlClass *klass)
                                      g_param_spec_string ("markup",
                                              "markup",
                                              "markup",
-                                             NULL,
+                                             nullptr,
                                              G_PARAM_WRITABLE));
 
     html_signals[LOAD_URL] =
@@ -325,7 +325,7 @@ _moo_html_class_init (MooHtmlClass *klass)
                           G_TYPE_FROM_CLASS (klass),
                           G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
                           G_STRUCT_OFFSET (MooHtmlClass, load_url),
-                          g_signal_accumulator_true_handled, NULL,
+                          g_signal_accumulator_true_handled, nullptr,
                           _moo_marshal_BOOLEAN__STRING,
                           G_TYPE_BOOLEAN, 1,
                           G_TYPE_STRING);
@@ -335,7 +335,7 @@ _moo_html_class_init (MooHtmlClass *klass)
                           G_TYPE_FROM_CLASS (klass),
                           G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
                           G_STRUCT_OFFSET (MooHtmlClass, hover_link),
-                          NULL, NULL,
+                          nullptr, nullptr,
                           _moo_marshal_VOID__STRING,
                           G_TYPE_NONE, 1,
                           G_TYPE_STRING);
@@ -348,15 +348,15 @@ moo_html_data_new (void)
     MooHtmlData *data = g_new0 (MooHtmlData, 1);
 
     data->anchors = g_hash_table_new_full (g_str_hash, g_str_equal,
-                                           g_free, NULL);
+                                           g_free, nullptr);
     data->root_tags = g_hash_table_new_full (g_str_hash, g_str_equal,
-                                             g_free, NULL);
-    data->href_tags = NULL;
-    data->doc = NULL;
+                                             g_free, nullptr);
+    data->href_tags = nullptr;
+    data->doc = nullptr;
 
-    data->filename = NULL;
-    data->basename = NULL;
-    data->dirname = NULL;
+    data->filename = nullptr;
+    data->basename = nullptr;
+    data->dirname = nullptr;
 
     data->font_sizes[0] = PANGO_SCALE_X_SMALL;
     data->font_sizes[1] = PANGO_SCALE_SMALL;
@@ -420,7 +420,7 @@ moo_html_get_data (GtkTextView* object)
         data = moo_html_data_new ();
         g_object_set_data_full(G_OBJECT(object), "moo-html-data", data,
                                 (GDestroyNotify) moo_html_data_free);
-        g_signal_connect (object, "size-allocate", G_CALLBACK (moo_html_size_allocate_cb), NULL);
+        g_signal_connect (object, "size-allocate", G_CALLBACK (moo_html_size_allocate_cb), nullptr);
     }
 
     return data;
@@ -437,7 +437,7 @@ _moo_html_init (MooHtml *html)
                   "editable", FALSE,
                   "wrap-mode", GTK_WRAP_WORD,
                   "pixels-below-lines", DEFAULT_PAR_SPACING,
-                  NULL);
+                  nullptr);
 }
 
 
@@ -476,7 +476,7 @@ moo_html_set_property (GObject        *object,
             if (!string)
                 string = "";
 
-            _moo_html_load_memory (GTK_TEXT_VIEW (html), string, -1, NULL, NULL);
+            _moo_html_load_memory (GTK_TEXT_VIEW (html), string, -1, nullptr, nullptr);
             break;
 
         default:
@@ -523,7 +523,7 @@ moo_html_load_url (GtkTextView *view,
     MooHtmlData *data = moo_html_get_data (view);
 
     g_return_val_if_fail (GTK_IS_TEXT_VIEW (view), FALSE);
-    g_return_val_if_fail (url != NULL, FALSE);
+    g_return_val_if_fail (url != nullptr, FALSE);
 
     if (!moo_html_parse_url (url, &scheme, &base, &anchor))
     {
@@ -537,7 +537,7 @@ moo_html_load_url (GtkTextView *view,
     if (!strcmp (scheme, "mailto:") ||
         !strcmp (scheme, "mailto://"))
     {
-        result = moo_open_email (base, NULL, NULL);
+        result = moo_open_email (base, nullptr, nullptr);
         goto out;
     }
 
@@ -555,9 +555,9 @@ moo_html_load_url (GtkTextView *view,
     {
         if (data->dirname)
         {
-            char *filename = g_build_filename (data->dirname, base, NULL);
+            char *filename = g_build_filename (data->dirname, base, nullptr);
 
-            result = _moo_html_load_file (view, filename, NULL);
+            result = _moo_html_load_file (view, filename, nullptr);
 
             if (result && anchor)
                 moo_html_goto_anchor (view, anchor);
@@ -567,7 +567,7 @@ moo_html_load_url (GtkTextView *view,
     }
     else
     {
-        result = _moo_html_load_file (view, base, NULL);
+        result = _moo_html_load_file (view, base, nullptr);
 
         if (result && anchor)
             moo_html_goto_anchor (view, anchor);
@@ -606,13 +606,13 @@ moo_html_clear (GtkTextView *view)
     MooHtmlData *data = moo_html_get_data (view);
 
     g_hash_table_destroy (data->anchors);
-    data->anchors = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
+    data->anchors = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, nullptr);
 
     buffer = gtk_text_view_get_buffer (view);
     table = gtk_text_buffer_get_tag_table (buffer);
     g_slist_foreach (data->href_tags, (GFunc) remove_tag, table);
     g_slist_free (data->href_tags);
-    data->href_tags = NULL;
+    data->href_tags = nullptr;
 
     gtk_text_buffer_get_bounds (buffer, &start, &end);
     gtk_text_buffer_delete (buffer, &start, &end);
@@ -622,10 +622,10 @@ moo_html_clear (GtkTextView *view)
 
     if (data->doc)
         xmlFreeDoc (data->doc);
-    data->doc = NULL;
+    data->doc = nullptr;
 
     g_slist_free (data->rulers);
-    data->rulers = NULL;
+    data->rulers = nullptr;
 }
 
 
@@ -634,8 +634,8 @@ moo_text_view_set_markup (GtkTextView *view,
                           const char  *markup)
 {
     g_return_if_fail (GTK_IS_TEXT_VIEW (view));
-    g_return_if_fail (markup != NULL);
-    _moo_html_load_memory (view, markup, -1, NULL, NULL);
+    g_return_if_fail (markup != nullptr);
+    _moo_html_load_memory (view, markup, -1, nullptr, nullptr);
 }
 
 
@@ -650,7 +650,7 @@ _moo_html_load_memory (GtkTextView *view,
     MooHtmlData *data;
 
     g_return_val_if_fail (GTK_IS_TEXT_VIEW (view), FALSE);
-    g_return_val_if_fail (buffer != NULL, FALSE);
+    g_return_val_if_fail (buffer != nullptr, FALSE);
 
     data = moo_html_get_data (view);
 
@@ -669,9 +669,9 @@ _moo_html_load_memory (GtkTextView *view,
     g_free (data->filename);
     g_free (data->basename);
     g_free (data->dirname);
-    data->filename = NULL;
-    data->basename = NULL;
-    data->dirname = NULL;
+    data->filename = nullptr;
+    data->basename = nullptr;
+    data->dirname = nullptr;
 
     moo_html_set_doc (view, doc);
 
@@ -689,7 +689,7 @@ _moo_html_load_file (GtkTextView *view,
     MooHtmlData *data = moo_html_get_data (view);
 
     g_return_val_if_fail (GTK_IS_TEXT_VIEW (view), FALSE);
-    g_return_val_if_fail (file != NULL, FALSE);
+    g_return_val_if_fail (file != nullptr, FALSE);
 
     doc = htmlReadFile (file, encoding, HTML_PARSE_NONET);
 
@@ -717,7 +717,7 @@ moo_html_set_doc (GtkTextView *view,
 {
     MooHtmlData *data;
 
-    g_return_if_fail (doc != NULL);
+    g_return_if_fail (doc != nullptr);
 
     data = moo_html_get_data (view);
     g_return_if_fail (doc != data->doc);
@@ -743,7 +743,7 @@ attr_compose (MooHtmlAttr       *dest,
     static MooHtmlAttrMask font_face_mask =
             MOO_HTML_FONT_FACE | MOO_HTML_MONOSPACE;
 
-    g_return_if_fail (dest != NULL);
+    g_return_if_fail (dest != nullptr);
 
     if (!src)
         return;
@@ -855,49 +855,49 @@ attr_apply (const MooHtmlAttr *attr,
 {
     MooHtmlData *data = moo_html_get_data (view);
 
-    g_return_if_fail (attr != NULL && tag != NULL);
+    g_return_if_fail (attr != nullptr && tag != nullptr);
 
     moo_html_attr_free (tag->attr);
     tag->attr = moo_html_attr_copy (attr);
 
     if (attr->mask & MOO_HTML_FG)
-        g_object_set (tag, "foreground", attr->fg, NULL);
+        g_object_set (tag, "foreground", attr->fg, nullptr);
     if (attr->mask & MOO_HTML_BG)
-        g_object_set (tag, "background", attr->bg, NULL);
+        g_object_set (tag, "background", attr->bg, nullptr);
     if (attr->mask & MOO_HTML_BOLD)
-        g_object_set (tag, "weight", PANGO_WEIGHT_BOLD, NULL);
+        g_object_set (tag, "weight", PANGO_WEIGHT_BOLD, nullptr);
     if (attr->mask & MOO_HTML_ITALIC)
-        g_object_set (tag, "style", PANGO_STYLE_ITALIC, NULL);
+        g_object_set (tag, "style", PANGO_STYLE_ITALIC, nullptr);
     if (attr->mask & MOO_HTML_UNDERLINE)
-        g_object_set (tag, "underline", PANGO_UNDERLINE_SINGLE, NULL);
+        g_object_set (tag, "underline", PANGO_UNDERLINE_SINGLE, nullptr);
     if (attr->mask & MOO_HTML_STRIKETHROUGH)
-        g_object_set (tag, "strikethrough", TRUE, NULL);
+        g_object_set (tag, "strikethrough", TRUE, nullptr);
 
     if (attr->mask & MOO_HTML_LEFT_MARGIN)
-        g_object_set (tag, "left-margin", attr->left_margin, NULL);
+        g_object_set (tag, "left-margin", attr->left_margin, nullptr);
 
     if (attr->mask & MOO_HTML_LINK)
     {
         g_free (tag->href);
         tag->href = g_strdup (attr->link);
-        g_object_set (tag, "foreground", "blue", NULL);
+        g_object_set (tag, "foreground", "blue", nullptr);
     }
 
     if (attr->mask & MOO_HTML_SUP)
         g_object_set (tag,
                       "rise", 8 * PANGO_SCALE,
                       "size", 8 * PANGO_SCALE,
-                      NULL);
+                      nullptr);
     if (attr->mask & MOO_HTML_SUB)
         g_object_set (tag,
                       "rise", -8 * PANGO_SCALE,
                       "size", 8 * PANGO_SCALE,
-                      NULL);
+                      nullptr);
 
     if (attr->mask & MOO_HTML_MONOSPACE)
-        g_object_set (tag, "font", data->monospace, NULL);
+        g_object_set (tag, "font", data->monospace, nullptr);
     else if (attr->mask & MOO_HTML_FONT_FACE)
-        g_object_set (tag, "font", attr->font_face, NULL);
+        g_object_set (tag, "font", attr->font_face, nullptr);
 
     if (attr->mask & MOO_HTML_HEADING)
     {
@@ -914,7 +914,7 @@ attr_apply (const MooHtmlAttr *attr,
         g_object_set (tag,
                       "scale", scale,
                       "pixels-below-lines", DEFAULT_PAR_SPACING + space,
-                      NULL);
+                      nullptr);
     }
     else if (attr->mask & MOO_HTML_SMALLER)
     {
@@ -927,7 +927,7 @@ attr_apply (const MooHtmlAttr *attr,
         g_object_set (tag,
                       "scale", scale,
                       "pixels-below-lines", DEFAULT_PAR_SPACING + space,
-                      NULL);
+                      nullptr);
     }
     else if (attr->mask & MOO_HTML_FONT_SIZE)
     {
@@ -936,11 +936,11 @@ attr_apply (const MooHtmlAttr *attr,
                       "scale", data->font_sizes[attr->font_size - 1],
                       "pixels-below-lines",
                       DEFAULT_PAR_SPACING + data->par_spacing[attr->font_size - 1],
-                      NULL);
+                      nullptr);
     }
     else if (attr->mask & MOO_HTML_FONT_PT_SIZE)
     {
-        g_object_set (tag, "size-points", (double) attr->font_pt_size, NULL);
+        g_object_set (tag, "size-points", (double) attr->font_pt_size, nullptr);
     }
 }
 
@@ -958,11 +958,11 @@ moo_html_make_heading_tag (GtkTextView    *view,
                   "pixels-below-lines",
                   DEFAULT_PAR_SPACING + data->heading_spacing[heading - 1],
                   "scale", data->heading_sizes[heading - 1],
-                  "weight", PANGO_WEIGHT_BOLD, NULL);
+                  "weight", PANGO_WEIGHT_BOLD, nullptr);
 
     if (data->heading_faces[heading - 1])
         g_object_set (tag, "family",
-                      data->heading_faces[heading - 1], NULL);
+                      data->heading_faces[heading - 1], nullptr);
 }
 
 
@@ -976,7 +976,7 @@ moo_html_create_tag (GtkTextView       *view,
     MooHtmlAttr real_attr;
     MooHtmlData *data = moo_html_get_data (view);
 
-    g_return_val_if_fail (attr != NULL, NULL);
+    g_return_val_if_fail (attr != nullptr, nullptr);
 
     if (!attr->mask && !force)
         return parent;
@@ -991,7 +991,7 @@ moo_html_create_tag (GtkTextView       *view,
         real_attr = *attr;
     }
 
-    tag = MOO_HTML_TAG (g_object_new (MOO_TYPE_HTML_TAG, (const char*) NULL));
+    tag = MOO_HTML_TAG (g_object_new (MOO_TYPE_HTML_TAG, (const char*) nullptr));
     gtk_text_tag_table_add (gtk_text_buffer_get_tag_table (gtk_text_view_get_buffer (view)),
                             GTK_TEXT_TAG (tag));
     g_object_unref (tag);
@@ -1010,7 +1010,7 @@ moo_html_attr_copy (const MooHtmlAttr *src)
 {
     MooHtmlAttr *attr;
 
-    g_return_val_if_fail (src != NULL, NULL);
+    g_return_val_if_fail (src != nullptr, nullptr);
 
     attr = g_new (MooHtmlAttr, 1);
 
@@ -1048,9 +1048,9 @@ moo_html_create_anchor (GtkTextView    *view,
     char *alt_name;
     MooHtmlData *data = moo_html_get_data (view);
 
-    g_return_if_fail (name != NULL && (name[0] != '#' || name[1]));
+    g_return_if_fail (name != nullptr && (name[0] != '#' || name[1]));
 
-    mark = gtk_text_buffer_create_mark (buffer, NULL, iter, TRUE);
+    mark = gtk_text_buffer_create_mark (buffer, nullptr, iter, TRUE);
 
     if (name[0] == '#')
         alt_name = g_strdup (name + 1);
@@ -1101,7 +1101,7 @@ moo_html_motion (GtkWidget      *widget,
 
     if (tag)
     {
-        g_return_val_if_fail (tag->href != NULL, FALSE);
+        g_return_val_if_fail (tag->href != nullptr, FALSE);
 
         if (!html->data->hover_link || strcmp (html->data->hover_link, tag->href))
         {
@@ -1122,13 +1122,13 @@ moo_html_motion (GtkWidget      *widget,
         GdkCursor *cursor;
 
         g_free (html->data->hover_link);
-        html->data->hover_link = NULL;
+        html->data->hover_link = nullptr;
 
         cursor = gdk_cursor_new (GDK_XTERM);
         gdk_window_set_cursor (event->window, cursor);
         gdk_cursor_unref (cursor);
 
-        g_signal_emit (html, html_signals[HOVER_LINK], 0, NULL);
+        g_signal_emit (html, html_signals[HOVER_LINK], 0, nullptr);
     }
 
 out:
@@ -1140,18 +1140,18 @@ static MooHtmlTag*
 moo_html_get_link_tag (GtkTextIter *iter)
 {
     MooHtmlTag *tag = moo_html_get_tag (iter);
-    return (tag && tag->href) ? tag : NULL;
+    return (tag && tag->href) ? tag : nullptr;
 }
 
 
 static MooHtmlTag*
 moo_html_get_tag (GtkTextIter *iter)
 {
-    MooHtmlTag *tag = NULL;
+    MooHtmlTag *tag = nullptr;
     GSList *l;
     GSList *list = gtk_text_iter_get_tags (iter);
 
-    for (l = list; l != NULL; l = l->next)
+    for (l = list; l != nullptr; l = l->next)
     {
         if (MOO_IS_HTML_TAG (l->data))
         {
@@ -1206,7 +1206,7 @@ moo_html_button_release (GtkWidget      *widget,
     if (tag)
     {
         gboolean result;
-        g_assert (tag->href != NULL);
+        g_assert (tag->href != nullptr);
         g_signal_emit (html, html_signals[LOAD_URL], 0, tag->href, &result);
     }
 
@@ -1224,11 +1224,11 @@ moo_html_parse_url (const char     *url,
     GRegex *regex;
     GMatchInfo *match_info;
 
-    g_return_val_if_fail (url != NULL, FALSE);
+    g_return_val_if_fail (url != nullptr, FALSE);
     g_return_val_if_fail (scheme && base && anchor, FALSE);
 
-    regex = g_regex_new ("^([a-zA-Z]+:(//)?)?([^#]*)(#(.*))?$", GRegexCompileFlags (0), GRegexMatchFlags (0), NULL);
-    g_return_val_if_fail (regex != NULL, FALSE);
+    regex = g_regex_new ("^([a-zA-Z]+:(//)?)?([^#]*)(#(.*))?$", GRegexCompileFlags (0), GRegexMatchFlags (0), nullptr);
+    g_return_val_if_fail (regex != nullptr, FALSE);
 
     if (!g_regex_match (regex, url, GRegexMatchFlags (0), &match_info))
     {
@@ -1241,9 +1241,9 @@ moo_html_parse_url (const char     *url,
     *base = g_match_info_fetch (match_info, 3);
     *anchor = g_match_info_fetch (match_info, 5);
 
-    if (!*scheme || !**scheme) {g_free (*scheme); *scheme = NULL;}
-    if (!*base || !**base) {g_free (*base); *base = NULL;}
-    if (!*anchor || !**anchor) {g_free (*anchor); *anchor = NULL;}
+    if (!*scheme || !**scheme) {g_free (*scheme); *scheme = nullptr;}
+    if (!*base || !**base) {g_free (*base); *base = nullptr;}
+    if (!*anchor || !**anchor) {g_free (*anchor); *anchor = nullptr;}
 
     g_match_info_free (match_info);
     g_regex_unref (regex);
@@ -1258,7 +1258,7 @@ moo_html_goto_anchor (GtkTextView *view,
     GtkTextMark *mark;
     MooHtmlData *data = moo_html_get_data (view);
 
-    g_return_val_if_fail (anchor != NULL, FALSE);
+    g_return_val_if_fail (anchor != nullptr, FALSE);
 
     mark = (GtkTextMark*) g_hash_table_lookup (data->anchors, anchor);
 
@@ -1284,10 +1284,10 @@ moo_html_set_font (MooHtml            *html,
     PangoFontDescription *font;
 
     g_return_if_fail (MOO_IS_HTML (html));
-    g_return_if_fail (string != NULL);
+    g_return_if_fail (string != nullptr);
 
     font = pango_font_description_from_string (string);
-    g_return_if_fail (font != NULL);
+    g_return_if_fail (font != nullptr);
 
     gtk_widget_modify_font (GTK_WIDGET (html), font);
     pango_font_description_free (font);
@@ -1299,7 +1299,7 @@ static void
 moo_html_size_allocate_real (GtkWidget *widget,
                              G_GNUC_UNUSED GtkAllocation *allocation)
 {
-    int border_width, child_width, height;
+    int border_width, child_width;
     GSList *l;
     GdkWindow *window;
     MooHtmlData *data = moo_html_get_data (GTK_TEXT_VIEW (widget));
@@ -1308,17 +1308,16 @@ moo_html_size_allocate_real (GtkWidget *widget,
         return;
 
     window = gtk_text_view_get_window (GTK_TEXT_VIEW (widget), GTK_TEXT_WINDOW_TEXT);
-    g_return_if_fail (window != NULL);
+    g_return_if_fail (window != nullptr);
 
     child_width = gdk_window_get_width (window);
-    height = gdk_window_get_height (window);
     border_width = gtk_container_get_border_width (GTK_CONTAINER (widget));
     child_width -= 2 * border_width + 2 * widget->style->xthickness +
             gtk_text_view_get_left_margin (GTK_TEXT_VIEW (widget)) +
             gtk_text_view_get_right_margin (GTK_TEXT_VIEW (widget));
     child_width = MAX (child_width, 0);
 
-    for (l = data->rulers; l != NULL; l = l->next)
+    for (l = data->rulers; l != nullptr; l = l->next)
     {
         GtkWidget *ruler = GTK_WIDGET (l->data);
         gtk_widget_set_size_request (ruler, child_width, -1);
@@ -1403,7 +1402,7 @@ moo_html_load_doc (GtkTextView *view,
         return;
     }
 
-    for (node = root->children; node != NULL; node = node->next)
+    for (node = root->children; node != nullptr; node = node->next)
     {
         if (IS_HEAD_ELEMENT (node))
         {
@@ -1427,7 +1426,7 @@ moo_html_load_head (GtkTextView *view,
 {
     xmlNode *child;
 
-    for (child = node->children; child != NULL; child = child->next)
+    for (child = node->children; child != nullptr; child = child->next)
     {
         if (IS_TITLE_ELEMENT (child))
         {
@@ -1462,7 +1461,7 @@ moo_html_new_line (GtkTextView   *view,
     {
         if (tag)
             gtk_text_buffer_insert_with_tags (buffer, iter, "\n", 1,
-                                              GTK_TEXT_TAG (tag), NULL);
+                                              GTK_TEXT_TAG (tag), nullptr);
         else
             gtk_text_buffer_insert (buffer, iter, "\n", 1);
     }
@@ -1483,7 +1482,7 @@ str_find_separator (const char *str)
             return p;
     }
 
-    return NULL;
+    return nullptr;
 }
 
 
@@ -1515,9 +1514,9 @@ moo_html_insert_text (GtkTextView   *view,
                 {
                     gtk_text_buffer_insert_with_tags (buffer, iter,
                                                       text, p - text,
-                                                      GTK_TEXT_TAG (tag), NULL);
+                                                      GTK_TEXT_TAG (tag), nullptr);
                     gtk_text_buffer_insert_with_tags (buffer, iter, " ", 1,
-                                                      GTK_TEXT_TAG (tag), NULL);
+                                                      GTK_TEXT_TAG (tag), nullptr);
                 }
                 else
                 {
@@ -1545,7 +1544,7 @@ moo_html_insert_text (GtkTextView   *view,
             if (tag)
                 gtk_text_buffer_insert_with_tags (buffer, iter,
                                                   text, -1,
-                                                  GTK_TEXT_TAG (tag), NULL);
+                                                  GTK_TEXT_TAG (tag), nullptr);
             else
                 gtk_text_buffer_insert (buffer, iter, text, -1);
             data->new_line = FALSE;
@@ -1595,7 +1594,7 @@ moo_html_insert_verbatim (GtkTextView   *view,
     guint len;
     MooHtmlData *data = moo_html_get_data (view);
 
-    g_return_if_fail (text != NULL);
+    g_return_if_fail (text != nullptr);
 
     if (text[0] == '\n' && data->new_line)
         text++;
@@ -1608,7 +1607,7 @@ moo_html_insert_verbatim (GtkTextView   *view,
     if (tag)
         gtk_text_buffer_insert_with_tags (buffer, iter,
                                           text, len,
-                                          GTK_TEXT_TAG (tag), NULL);
+                                          GTK_TEXT_TAG (tag), nullptr);
     else
         gtk_text_buffer_insert (buffer, iter, text, len);
 
@@ -1696,7 +1695,7 @@ moo_html_load_body (GtkTextView *view,
     buffer = gtk_text_view_get_buffer (view);
     gtk_text_buffer_get_end_iter (buffer, &iter);
 
-    process_elm_body (view, buffer, node, NULL, &iter);
+    process_elm_body (view, buffer, node, nullptr, &iter);
 }
 
 
@@ -1708,11 +1707,11 @@ typedef struct {
 static MooHtmlAttr*
 get_format_elm_attr (xmlNode *node)
 {
-    static GHashTable *elms = NULL;
+    static GHashTable *elms = nullptr;
     MooHtmlAttr *attr;
 
     if (!IS_ELEMENT (node))
-        return NULL;
+        return nullptr;
 
     if (!elms)
     {
@@ -1765,7 +1764,7 @@ get_format_elm_attr (xmlNode *node)
 typedef void (*ProcessElm) (GtkTextView *view, GtkTextBuffer *buffer, xmlNode *elm,
                             MooHtmlTag *parent, GtkTextIter *iter);
 
-static GHashTable *proc_elm_funcs__ = NULL;
+static GHashTable *proc_elm_funcs__ = nullptr;
 
 static void
 add_func__ (const char *static_elm_name,
@@ -1807,7 +1806,7 @@ get_proc_elm_func (xmlNode *node)
     if (IS_ELEMENT (node))
         return (ProcessElm) g_hash_table_lookup (proc_elm_funcs__, node->name);
     else
-        return NULL;
+        return nullptr;
 }
 
 
@@ -1822,7 +1821,7 @@ process_elm_body (GtkTextView    *view,
     MooHtmlAttr *attr;
     ProcessElm func;
 
-    for (child = elm->children; child != NULL; child = child->next)
+    for (child = elm->children; child != nullptr; child = child->next)
     {
 
         if (IS_TEXT (child))
@@ -1964,7 +1963,7 @@ parse_int (const char *str,
         return FALSE;
 
     errno = 0;
-    num = strtol (str, NULL, 10);
+    num = strtol (str, nullptr, 10);
 
     if (errno)
         return FALSE;
@@ -1993,7 +1992,7 @@ static char*
 make_li_number (int     count,
                 OLType  type)
 {
-    g_return_val_if_fail (count > 0, NULL);
+    g_return_val_if_fail (count > 0, nullptr);
 
     switch (type)
     {
@@ -2003,14 +2002,14 @@ make_li_number (int     count,
         case OL_NUM:
             return g_strdup_printf (" %d. ", count);
         case OL_LOWER_ALPHA:
-            g_return_val_if_fail (count <= 26, NULL);
+            g_return_val_if_fail (count <= 26, nullptr);
             return g_strdup_printf (" %c. ", count - 1 + 'a');
         case OL_UPPER_ALPHA:
-            g_return_val_if_fail (count <= 26, NULL);
+            g_return_val_if_fail (count <= 26, nullptr);
             return g_strdup_printf (" %c. ", count - 1 + 'A');
     }
 
-    g_return_val_if_reached (NULL);
+    g_return_val_if_reached (nullptr);
 }
 
 static void
@@ -2023,7 +2022,7 @@ process_ol_elm (GtkTextView    *view,
     int count;
     OLType list_type = OL_NUM;
     xmlNode *child;
-    xmlChar *start = NULL, *type = NULL;
+    xmlChar *start = nullptr, *type = nullptr;
     MooHtmlData *data = moo_html_get_data (view);
 
     count = 1;
@@ -2051,7 +2050,7 @@ process_ol_elm (GtkTextView    *view,
 
     moo_html_new_line (view, buffer, iter, current, FALSE);
 
-    for (child = elm->children; child != NULL; child = child->next)
+    for (child = elm->children; child != nullptr; child = child->next)
     {
         if (IS_LI_ELEMENT (child))
         {
@@ -2094,7 +2093,7 @@ process_ul_elm (GtkTextView    *view,
                 GtkTextIter    *iter)
 {
     xmlNode *child;
-    for (child = elm->children; child != NULL; child = child->next)
+    for (child = elm->children; child != nullptr; child = child->next)
         process_elm_body (view, buffer, child, current, iter);
 }
 
@@ -2156,7 +2155,7 @@ process_font_elm (GtkTextView   *view,
     face = GET_PROP (elm, "face");
 
     attr.mask = MOO_HTML_NONE;
-    attr.font_face = NULL;
+    attr.font_face = nullptr;
 
     if (size__)
     {
@@ -2349,9 +2348,9 @@ process_img_elm (GtkTextView    *view,
 {
     xmlChar *src;
     xmlChar *alt;
-    char *path = NULL;
+    char *path = nullptr;
     GdkPixbuf *pixbuf;
-    GError *error = NULL;
+    GError *error = nullptr;
     int offset;
     GtkTextIter before;
     MooHtmlData *data = moo_html_get_data (view);
@@ -2359,13 +2358,13 @@ process_img_elm (GtkTextView    *view,
     src = GET_PROP (elm, "src");
     alt = GET_PROP (elm, "alt");
 
-    g_return_if_fail (src != NULL);
+    g_return_if_fail (src != nullptr);
 
     if (!data->dirname)
         goto try_alt;
 
-    path = g_build_filename (data->dirname, src, NULL);
-    g_return_if_fail (path != NULL);
+    path = g_build_filename (data->dirname, src, nullptr);
+    g_return_if_fail (path != nullptr);
 
     pixbuf = gdk_pixbuf_new_from_file (path, &error);
 
diff --git a/moo/mooedit/mooeditaction.cpp b/moo/mooedit/mooeditaction.cpp
index e1fafa35..62ce6dd2 100644
--- a/moo/mooedit/mooeditaction.cpp
+++ b/moo/mooedit/mooeditaction.cpp
@@ -283,7 +283,7 @@ moo_edit_action_check_state_real (MooEditAction *action)
     visible = moo_edit_action_check_visible (action);
     sensitive = moo_edit_action_check_sensitive (action);
 
-    g_object_set (action, "sensitive", sensitive, "visible", visible, NULL);
+    g_object_set (action, "sensitive", sensitive, "visible", visible, nullptr);
 }
 
 
diff --git a/moo/mooedit/mooeditdialogs.cpp b/moo/mooedit/mooeditdialogs.cpp
index af32b4f3..110590bf 100644
--- a/moo/mooedit/mooeditdialogs.cpp
+++ b/moo/mooedit/mooeditdialogs.cpp
@@ -47,7 +47,7 @@ _moo_edit_open_dialog (GtkWidget *widget,
     MooOpenInfoArray *info_array = NULL;
     guint i;
 
-    moo_prefs_create_key (moo_edit_setting (MOO_EDIT_PREFS_LAST_DIR), MOO_PREFS_STATE, G_TYPE_STRING, NULL);
+    moo_prefs_create_key (moo_edit_setting (MOO_EDIT_PREFS_LAST_DIR), MOO_PREFS_STATE, G_TYPE_STRING, nullptr);
 
     if (current_doc && moo_prefs_get_bool (moo_edit_setting (MOO_EDIT_PREFS_DIALOGS_OPEN_FOLLOWS_DOC)))
     {
@@ -64,8 +64,8 @@ _moo_edit_open_dialog (GtkWidget *widget,
 
     dialog = moo_file_dialog_new (MOO_FILE_DIALOG_OPEN, widget,
                                   TRUE, GTK_STOCK_OPEN, start,
-                                  NULL);
-    g_object_set (dialog, "enable-encodings", TRUE, NULL);
+                                  nullptr);
+    g_object_set (dialog, "enable-encodings", TRUE, nullptr);
     moo_file_dialog_set_help_id (dialog, "dialog-open");
     moo_file_dialog_set_remember_size (dialog, moo_edit_setting (MOO_EDIT_PREFS_DIALOG_OPEN));
 
@@ -107,7 +107,7 @@ _moo_edit_save_as_dialog (MooEdit    *doc,
     GFile *start = NULL;
     GFile *file = NULL;
 
-    g_return_val_if_fail (MOO_IS_EDIT (doc), NULL);
+    g_return_val_if_fail (MOO_IS_EDIT (doc), nullptr);
 
     moo_prefs_create_key (moo_edit_setting (MOO_EDIT_PREFS_LAST_DIR),
                           MOO_PREFS_STATE, G_TYPE_STRING, NULL);
@@ -128,7 +128,7 @@ _moo_edit_save_as_dialog (MooEdit    *doc,
                                   GTK_WIDGET (moo_edit_get_view (doc)),
                                   FALSE, GTK_STOCK_SAVE_AS,
                                   start, display_basename);
-    g_object_set (dialog, "enable-encodings", TRUE, NULL);
+    g_object_set (dialog, "enable-encodings", TRUE, nullptr);
     moo_file_dialog_set_encoding (dialog, moo_edit_get_encoding (doc));
     moo_file_dialog_set_help_id (dialog, "dialog-save");
 
@@ -252,7 +252,7 @@ name_data_func (G_GNUC_UNUSED GtkTreeViewColumn *column,
     gtk_tree_model_get (model, iter, COLUMN_EDIT, &doc, -1);
     g_return_if_fail (MOO_IS_EDIT (doc));
 
-    g_object_set (cell, "text", moo_edit_get_display_basename (doc), NULL);
+    g_object_set (cell, "text", moo_edit_get_display_basename (doc), nullptr);
     g_object_unref (doc);
 }
 
@@ -337,7 +337,7 @@ files_treeview_init (GtkTreeView *treeview, GtkWidget *dialog, MooEditArray *doc
     gtk_tree_view_append_column (treeview, column);
     cell = gtk_cell_renderer_toggle_new ();
     gtk_tree_view_column_pack_start (column, cell, FALSE);
-    g_object_set (cell, "activatable", TRUE, NULL);
+    g_object_set (cell, "activatable", TRUE, nullptr);
     gtk_tree_view_column_add_attribute (column, cell, "active", COLUMN_SAVE);
     g_signal_connect (cell, "toggled", G_CALLBACK (save_toggled), store);
 
@@ -429,7 +429,7 @@ _moo_edit_save_multiple_changes_dialog (MooEditArray *docs,
                             MOO_STOCK_SAVE_NONE, GTK_RESPONSE_NO,
                             GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
                             MOO_STOCK_SAVE_SELECTED, GTK_RESPONSE_YES,
-                            NULL);
+                            nullptr);
 
     gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_YES);
 
@@ -530,7 +530,7 @@ moo_edit_question_dialog (MooEdit    *doc,
     gtk_dialog_add_buttons (GTK_DIALOG (dialog),
                             GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
                             button, GTK_RESPONSE_YES,
-                            NULL);
+                            nullptr);
 
     gtk_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
                                              GTK_RESPONSE_YES,
@@ -623,7 +623,7 @@ _moo_edit_try_encoding_dialog (G_GNUC_UNUSED GFile *file,
     gtk_dialog_add_buttons (GTK_DIALOG (dialog),
                             GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
                             GTK_STOCK_OK, GTK_RESPONSE_OK,
-                            NULL);
+                            nullptr);
     gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_OK);
     gtk_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
                                              GTK_RESPONSE_OK,
@@ -779,7 +779,7 @@ _moo_text_search_from_start_dialog (GtkWidget *widget,
     gtk_dialog_add_buttons (GTK_DIALOG (dialog),
                             GTK_STOCK_NO, GTK_RESPONSE_CANCEL,
                             GTK_STOCK_YES, GTK_RESPONSE_YES,
-                            NULL);
+                            nullptr);
     gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_YES);
     gtk_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
                                              GTK_RESPONSE_YES,
@@ -817,7 +817,7 @@ _moo_text_regex_error_dialog (GtkWidget  *parent,
                                      "%s", msg_text);
     moo_window_set_parent (dialog, parent);
     gtk_dialog_add_buttons (GTK_DIALOG (dialog), GTK_STOCK_CLOSE,
-                            GTK_RESPONSE_CANCEL, NULL);
+                            GTK_RESPONSE_CANCEL, nullptr);
     gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_CANCEL);
 
     gtk_dialog_run (GTK_DIALOG (dialog));
diff --git a/moo/mooedit/mooeditor.cpp b/moo/mooedit/mooeditor.cpp
index ce4498af..b908b5c6 100644
--- a/moo/mooedit/mooeditor.cpp
+++ b/moo/mooedit/mooeditor.cpp
@@ -334,7 +334,7 @@ moo_editor_class_init (MooEditorClass *klass)
                                  "label", Q_("Open Recent|_More..."),
                                  "default-accel", MOO_EDIT_ACCEL_OPEN_RECENT_DIALOG,
                                  "closure-callback", action_recent_dialog,
-                                 NULL);
+                                 nullptr);
     g_type_class_unref (edit_window_class);
 
     add_new_window_action ();
@@ -602,7 +602,7 @@ add_new_window_action (void)
                                      "default-accel", MOO_EDIT_ACCEL_NEW_WINDOW,
                                      "closure-callback", moo_editor_new_window,
                                      "closure-proxy-func", moo_edit_window_get_editor,
-                                     NULL);
+                                     nullptr);
 }
 
 
@@ -2997,7 +2997,7 @@ _moo_editor_apply_prefs (MooEditor *editor)
 
     g_object_set (editor,
                   "save-backups", backups,
-                  NULL);
+                  nullptr);
 }
 
 
diff --git a/moo/mooedit/mooeditprefs.cpp b/moo/mooedit/mooeditprefs.cpp
index 6de4b028..7fbce596 100644
--- a/moo/mooedit/mooeditprefs.cpp
+++ b/moo/mooedit/mooeditprefs.cpp
@@ -211,7 +211,7 @@ _moo_edit_update_global_config (void)
                                 "add-newline", add_newline,
                                 "show-line-numbers", show_line_numbers,
                                 "wrap-mode", wrap_mode,
-                                NULL);
+                                nullptr);
 }
 
 
@@ -248,9 +248,9 @@ _moo_edit_view_apply_prefs (MooEditView *view)
                   "auto-indent", get_bool (MOO_EDIT_PREFS_AUTO_INDENT),
                   "tab-indents", get_bool (MOO_EDIT_PREFS_TAB_INDENTS),
                   "backspace-indents", get_bool (MOO_EDIT_PREFS_BACKSPACE_INDENTS),
-                  NULL);
+                  nullptr);
 
-    g_object_set (view, "draw-whitespace", ws_flags, NULL);
+    g_object_set (view, "draw-whitespace", ws_flags, nullptr);
 
     moo_text_view_set_font_from_string (MOO_TEXT_VIEW (view),
                                         get_string (MOO_EDIT_PREFS_FONT));
diff --git a/moo/mooedit/mooeditprefspage.cpp b/moo/mooedit/mooeditprefspage.cpp
index 32a2ca85..513c7da8 100644
--- a/moo/mooedit/mooeditprefspage.cpp
+++ b/moo/mooedit/mooeditprefspage.cpp
@@ -140,7 +140,7 @@ page_general_init (MooPrefsPage *page)
     {
         MooTextStyleScheme *scheme;
 
-        g_object_set (gxml->fontbutton, "monospace", TRUE, NULL);
+        g_object_set (gxml->fontbutton, "monospace", TRUE, nullptr);
 
         scheme = moo_lang_mgr_get_active_scheme (moo_lang_mgr_default ());
         g_return_if_fail (scheme != NULL);
@@ -407,7 +407,7 @@ scheme_combo_data_func (G_GNUC_UNUSED GtkCellLayout *layout,
     MooTextStyleScheme *scheme = NULL;
     gtk_tree_model_get (model, iter, 0, &scheme, -1);
     g_return_if_fail (scheme != NULL);
-    g_object_set (cell, "text", moo_text_style_scheme_get_name (scheme), NULL);
+    g_object_set (cell, "text", moo_text_style_scheme_get_name (scheme), nullptr);
     g_object_unref (scheme);
 }
 
@@ -652,7 +652,7 @@ set_sensitive (G_GNUC_UNUSED GtkCellLayout *cell_layout,
 {
     g_object_set (cell, "sensitive",
                   !gtk_tree_model_iter_has_child (model, iter),
-                  NULL);
+                  nullptr);
 }
 
 
@@ -733,7 +733,7 @@ lang_combo_init (GtkComboBox   *combo,
     gtk_cell_layout_clear (GTK_CELL_LAYOUT (combo));
     gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (combo), cell, TRUE);
     gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (combo), cell,
-                                    "text", COLUMN_NAME, NULL);
+                                    "text", COLUMN_NAME, nullptr);
     gtk_cell_layout_set_cell_data_func (GTK_CELL_LAYOUT (combo), cell,
                                         set_sensitive, NULL, NULL);
 
@@ -987,7 +987,7 @@ filter_icon_data_func (G_GNUC_UNUSED GtkTreeViewColumn *column,
 {
     gboolean invalid;
     gtk_tree_model_get (model, iter, FILTER_COLUMN_INVALID, &invalid, -1);
-    g_object_set (cell, "visible", invalid, NULL);
+    g_object_set (cell, "visible", invalid, nullptr);
 }
 
 static void
@@ -1006,7 +1006,7 @@ create_filter_column (GtkTreeView  *treeview,
     if (column_id == FILTER_COLUMN_FILTER)
     {
         cell = gtk_cell_renderer_pixbuf_new ();
-        g_object_set (cell, "stock-id", GTK_STOCK_DIALOG_ERROR, NULL);
+        g_object_set (cell, "stock-id", GTK_STOCK_DIALOG_ERROR, nullptr);
         gtk_tree_view_column_pack_start (column, cell, FALSE);
         gtk_tree_view_column_set_cell_data_func (column, cell,
                                                  (GtkTreeCellDataFunc) filter_icon_data_func,
@@ -1015,9 +1015,9 @@ create_filter_column (GtkTreeView  *treeview,
 
     cell = gtk_cell_renderer_text_new ();
     gtk_tree_view_column_pack_start (column, cell, TRUE);
-    gtk_tree_view_column_set_attributes (column, cell, "text", column_id, NULL);
+    gtk_tree_view_column_set_attributes (column, cell, "text", column_id, nullptr);
 
-    g_object_set (cell, "editable", TRUE, NULL);
+    g_object_set (cell, "editable", TRUE, nullptr);
     g_object_set_data (G_OBJECT (cell), "filter-store-column-id", GINT_TO_POINTER (column_id));
     g_signal_connect (cell, "edited", G_CALLBACK (filter_cell_edited), store);
 }
diff --git a/moo/mooedit/mooeditview.cpp b/moo/mooedit/mooeditview.cpp
index de6edb24..70c2adf0 100644
--- a/moo/mooedit/mooeditview.cpp
+++ b/moo/mooedit/mooeditview.cpp
@@ -437,7 +437,7 @@ _moo_edit_view_ui_set_line_wrap (MooEditView *view,
     g_return_if_fail (MOO_IS_EDIT_VIEW (view));
     g_return_if_fail (view->priv->doc && view->priv->doc->config);
 
-    g_object_get (view, "wrap-mode", &mode, NULL);
+    g_object_get (view, "wrap-mode", &mode, nullptr);
 
     enabled = enabled != 0;
     old_enabled = mode != GTK_WRAP_NONE;
@@ -454,7 +454,7 @@ _moo_edit_view_ui_set_line_wrap (MooEditView *view,
 
     moo_edit_config_set (view->priv->doc->config,
                          MOO_EDIT_CONFIG_SOURCE_USER,
-                         "wrap-mode", mode, NULL);
+                         "wrap-mode", mode, nullptr);
 }
 
 void
@@ -466,7 +466,7 @@ _moo_edit_view_ui_set_show_line_numbers (MooEditView *view,
     g_return_if_fail (MOO_IS_EDIT_VIEW (view));
     g_return_if_fail (view->priv->doc && view->priv->doc->config);
 
-    g_object_get (view, "show-line-numbers", &old_show, NULL);
+    g_object_get (view, "show-line-numbers", &old_show, nullptr);
 
     if (!old_show == !show)
         return;
diff --git a/moo/mooedit/mooeditwindow.cpp b/moo/mooedit/mooeditwindow.cpp
index c061e071..1f24f7b4 100644
--- a/moo/mooedit/mooeditwindow.cpp
+++ b/moo/mooedit/mooeditwindow.cpp
@@ -383,7 +383,7 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                           G_OBJECT_CLASS_TYPE (klass),
                           G_SIGNAL_RUN_LAST,
                           G_STRUCT_OFFSET (MooEditWindowClass, will_close),
-                          NULL, NULL,
+                          nullptr, nullptr,
                           _moo_marshal_VOID__VOID,
                           G_TYPE_NONE, 0);
 
@@ -392,7 +392,7 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                           G_OBJECT_CLASS_TYPE (klass),
                           G_SIGNAL_RUN_LAST,
                           G_STRUCT_OFFSET (MooEditWindowClass, new_doc),
-                          NULL, NULL,
+                          nullptr, nullptr,
                           _moo_marshal_VOID__OBJECT,
                           G_TYPE_NONE, 1,
                           MOO_TYPE_EDIT);
@@ -402,7 +402,7 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                           G_OBJECT_CLASS_TYPE (klass),
                           G_SIGNAL_RUN_LAST,
                           G_STRUCT_OFFSET (MooEditWindowClass, close_doc),
-                          NULL, NULL,
+                          nullptr, nullptr,
                           _moo_marshal_VOID__OBJECT,
                           G_TYPE_NONE, 1,
                           MOO_TYPE_EDIT);
@@ -412,7 +412,7 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                           G_OBJECT_CLASS_TYPE (klass),
                           G_SIGNAL_RUN_LAST,
                           G_STRUCT_OFFSET (MooEditWindowClass, close_doc_after),
-                          NULL, NULL,
+                          nullptr, nullptr,
                           _moo_marshal_VOID__VOID,
                           G_TYPE_NONE, 0);
 
@@ -425,25 +425,25 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
 
     moo_window_class_set_id (window_class, "Editor", "Editor");
 
-    moo_window_class_new_action (window_class, "NewDoc", NULL,
+    moo_window_class_new_action (window_class, "NewDoc", nullptr,
                                  "display-name", GTK_STOCK_NEW,
                                  "label", GTK_STOCK_NEW,
                                  "tooltip", _("Create new document"),
                                  "stock-id", GTK_STOCK_NEW,
                                  "default-accel", MOO_EDIT_ACCEL_NEW,
                                  "closure-callback", action_new_doc,
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Open", NULL,
+    moo_window_class_new_action (window_class, "Open", nullptr,
                                  "display-name", GTK_STOCK_OPEN,
                                  "label", _("_Open..."),
                                  "tooltip", _("Open..."),
                                  "stock-id", GTK_STOCK_OPEN,
                                  "default-accel", MOO_EDIT_ACCEL_OPEN,
                                  "closure-callback", action_open,
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Reload", NULL,
+    moo_window_class_new_action (window_class, "Reload", nullptr,
                                  "display-name", _("Reload"),
                                  "label", _("_Reload"),
                                  "tooltip", _("Reload document"),
@@ -451,21 +451,21 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "default-accel", MOO_EDIT_ACCEL_RELOAD,
                                  "closure-callback", action_reload,
                                  "condition::sensitive", "can-reload",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action_custom (window_class, "ReopenWithEncoding", NULL,
+    moo_window_class_new_action_custom (window_class, "ReopenWithEncoding", nullptr,
                                         (MooWindowActionFunc) create_reopen_with_encoding_action,
-                                        NULL, NULL);
+                                        nullptr, nullptr);
 
-    moo_window_class_new_action_custom (window_class, "EncodingMenu", NULL,
+    moo_window_class_new_action_custom (window_class, "EncodingMenu", nullptr,
                                         (MooWindowActionFunc) create_doc_encoding_action,
-                                        NULL, NULL);
+                                        nullptr, nullptr);
 
-    moo_window_class_new_action_custom (window_class, "LineEndMenu", NULL,
+    moo_window_class_new_action_custom (window_class, "LineEndMenu", nullptr,
                                         (MooWindowActionFunc) create_doc_line_end_action,
-                                        NULL, NULL);
+                                        nullptr, nullptr);
 
-    moo_window_class_new_action (window_class, "Save", NULL,
+    moo_window_class_new_action (window_class, "Save", nullptr,
                                  "display-name", GTK_STOCK_SAVE,
                                  "label", GTK_STOCK_SAVE,
                                  "tooltip", GTK_STOCK_SAVE,
@@ -473,9 +473,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "default-accel", MOO_EDIT_ACCEL_SAVE,
                                  "closure-callback", action_save,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "SaveAs", NULL,
+    moo_window_class_new_action (window_class, "SaveAs", nullptr,
                                  "display-name", GTK_STOCK_SAVE_AS,
                                  "label", _("Save _As..."),
                                  "tooltip", _("Save as..."),
@@ -483,9 +483,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "default-accel", MOO_EDIT_ACCEL_SAVE_AS,
                                  "closure-callback", action_save_as,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Close", NULL,
+    moo_window_class_new_action (window_class, "Close", nullptr,
                                  "display-name", GTK_STOCK_CLOSE,
                                  "label", GTK_STOCK_CLOSE,
                                  "tooltip", _("Close document"),
@@ -493,18 +493,18 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "default-accel", MOO_EDIT_ACCEL_CLOSE,
                                  "closure-callback", action_close_tab,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "CloseAll", NULL,
+    moo_window_class_new_action (window_class, "CloseAll", nullptr,
                                  "display-name", _("Close All"),
                                  "label", _("Close A_ll"),
                                  "tooltip", _("Close all documents"),
                                  "default-accel", MOO_EDIT_ACCEL_CLOSE_ALL,
                                  "closure-callback", action_close_all,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "PreviousTab", NULL,
+    moo_window_class_new_action (window_class, "PreviousTab", nullptr,
                                  "display-name", _("Previous Tab"),
                                  "label", _("_Previous Tab"),
                                  "tooltip", _("Previous tab"),
@@ -512,9 +512,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "default-accel", MOO_EDIT_ACCEL_PREV_TAB,
                                  "closure-callback", action_previous_tab,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "NextTab", NULL,
+    moo_window_class_new_action (window_class, "NextTab", nullptr,
                                  "display-name", _("Next Tab"),
                                  "label", _("_Next Tab"),
                                  "tooltip", _("Next tab"),
@@ -522,27 +522,27 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "default-accel", MOO_EDIT_ACCEL_NEXT_TAB,
                                  "closure-callback", action_next_tab,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "PreviousTabInView", NULL,
+    moo_window_class_new_action (window_class, "PreviousTabInView", nullptr,
                                  "display-name", _("Previous Tab In View"),
                                  "label", _("_Previous Tab In View"),
                                  "tooltip", _("Previous tab in view"),
                                  "default-accel", MOO_EDIT_ACCEL_PREV_TAB_IN_VIEW,
                                  "closure-callback", action_previous_tab_in_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "NextTabInView", NULL,
+    moo_window_class_new_action (window_class, "NextTabInView", nullptr,
                                  "display-name", _("Next Tab In View"),
                                  "label", _("_Next Tab In View"),
                                  "tooltip", _("Next tab in view"),
                                  "default-accel", MOO_EDIT_ACCEL_NEXT_TAB_IN_VIEW,
                                  "closure-callback", action_next_tab_in_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Find", NULL,
+    moo_window_class_new_action (window_class, "Find", nullptr,
                                  "display-name", GTK_STOCK_FIND,
                                  "label", GTK_STOCK_FIND,
                                  "tooltip", GTK_STOCK_FIND,
@@ -551,9 +551,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-signal", "find-interactive",
                                  "closure-proxy-func", moo_edit_window_get_active_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "FindNext", NULL,
+    moo_window_class_new_action (window_class, "FindNext", nullptr,
                                  "display-name", _("Find Next"),
                                  "label", _("Find _Next"),
                                  "tooltip", _("Find next"),
@@ -562,9 +562,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-signal", "find-next-interactive",
                                  "closure-proxy-func", moo_edit_window_get_active_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "FindPrevious", NULL,
+    moo_window_class_new_action (window_class, "FindPrevious", nullptr,
                                  "display-name", _("Find Previous"),
                                  "label", _("Find _Previous"),
                                  "tooltip", _("Find previous"),
@@ -573,9 +573,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-signal", "find-prev-interactive",
                                  "closure-proxy-func", moo_edit_window_get_active_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Replace", NULL,
+    moo_window_class_new_action (window_class, "Replace", nullptr,
                                  "display-name", GTK_STOCK_FIND_AND_REPLACE,
                                  "label", GTK_STOCK_FIND_AND_REPLACE,
                                  "tooltip", GTK_STOCK_FIND_AND_REPLACE,
@@ -584,27 +584,27 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-signal", "replace-interactive",
                                  "closure-proxy-func", moo_edit_window_get_active_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "FindCurrent", NULL,
+    moo_window_class_new_action (window_class, "FindCurrent", nullptr,
                                  "display-name", _("Find Current Word"),
                                  "label", _("Find Current _Word"),
                                  "stock-id", GTK_STOCK_FIND,
                                  "default-accel", MOO_EDIT_ACCEL_FIND_CURRENT,
                                  "closure-callback", action_find_now_f,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "FindCurrentBack", NULL,
+    moo_window_class_new_action (window_class, "FindCurrentBack", nullptr,
                                  "display-name", _("Find Current Word Backwards"),
                                  "label", _("Find Current Word _Backwards"),
                                  "stock-id", GTK_STOCK_FIND,
                                  "default-accel", MOO_EDIT_ACCEL_FIND_CURRENT_BACK,
                                  "closure-callback", action_find_now_b,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "GoToLine", NULL,
+    moo_window_class_new_action (window_class, "GoToLine", nullptr,
                                  "display-name", _("Go to Line"),
                                  "label", _("_Go to Line..."),
                                  "tooltip", _("Go to line..."),
@@ -612,72 +612,72 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-signal", "goto-line-interactive",
                                  "closure-proxy-func", moo_edit_window_get_active_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "WrapText", NULL,
+    moo_window_class_new_action (window_class, "WrapText", nullptr,
                                  "action-type::", MOO_TYPE_TOGGLE_ACTION,
                                  "display-name", _("Toggle Text Wrapping"),
                                  "label", _("_Wrap Text"),
                                  "toggled-callback", wrap_text_toggled,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "LineNumbers", NULL,
+    moo_window_class_new_action (window_class, "LineNumbers", nullptr,
                                  "action-type::", MOO_TYPE_TOGGLE_ACTION,
                                  "display-name", _("Toggle Line Numbers Display"),
                                  "label", _("Show _Line Numbers"),
                                  "toggled-callback", line_numbers_toggled,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "FocusDoc", NULL,
+    moo_window_class_new_action (window_class, "FocusDoc", nullptr,
                                  "display-name", _("Focus Document"),
                                  "label", _("_Focus Document"),
                                  "default-accel", MOO_EDIT_ACCEL_FOCUS_DOC,
                                  "closure-callback", action_focus_doc,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "FocusOtherSplitNotebook", NULL,
+    moo_window_class_new_action (window_class, "FocusOtherSplitNotebook", nullptr,
                                  "display-name", _("Focus Other Split Notebook"),
                                  "label", _("Focus Other Split Notebook"),
                                  "default-accel", MOO_EDIT_ACCEL_FOCUS_SPLIT_NOTEBOOK,
                                  "closure-callback", action_focus_other_split_notebook,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "MoveToSplitView", NULL,
+    moo_window_class_new_action (window_class, "MoveToSplitView", nullptr,
                                  "display-name", _("Move to Split Notebook"),
                                  "label", _("_Move to Split Notebook"),
                                  "default-accel", MOO_EDIT_ACCEL_MOVE_TO_SPLIT_NOTEBOOK,
                                  "closure-callback", action_move_to_split_notebook,
                                  "condition::sensitive", "can-move-to-split-notebook",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "SplitViewHorizontal", NULL,
+    moo_window_class_new_action (window_class, "SplitViewHorizontal", nullptr,
                                  "action-type::", MOO_TYPE_TOGGLE_ACTION,
                                  "display-name", _("Split View Horizontally"),
                                  "label", _("Split View Horizontally"),
                                  "toggled-callback", split_view_horizontal_toggled,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "SplitViewVertical", NULL,
+    moo_window_class_new_action (window_class, "SplitViewVertical", nullptr,
                                  "action-type::", MOO_TYPE_TOGGLE_ACTION,
                                  "display-name", _("Split View Vertically"),
                                  "label", _("Split View Vertically"),
                                  "toggled-callback", split_view_vertical_toggled,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "CycleSplitViews", NULL,
+    moo_window_class_new_action (window_class, "CycleSplitViews", nullptr,
                                  "display-name", _("Focus Next Split View"),
                                  "label", _("Focus Next Split View"),
                                  "closure-callback", action_focus_next_split_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, STOP_ACTION_ID, NULL,
+    moo_window_class_new_action (window_class, STOP_ACTION_ID, nullptr,
                                  "display-name", GTK_STOCK_STOP,
                                  "label", GTK_STOCK_STOP,
                                  "tooltip", GTK_STOCK_STOP,
@@ -686,13 +686,13 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-callback", action_abort_jobs,
                                  "condition::sensitive", "has-jobs-running",
                                  "condition::visible", "has-stop-clients",
-                                 NULL);
+                                 nullptr);
 
     for (i = 1; i < 10; ++i)
     {
         char *action_id = g_strdup_printf (DOCUMENT_ACTION "%u", i);
         char *accel = g_strdup_printf (MOO_EDIT_ACCEL_SWITCH_TO_TAB "%u", i);
-        _moo_window_class_new_action_callback (window_class, action_id, NULL,
+        _moo_window_class_new_action_callback (window_class, action_id, nullptr,
                                                G_CALLBACK (action_switch_to_tab),
                                                _moo_marshal_VOID__UINT,
                                                G_TYPE_NONE, 1,
@@ -700,7 +700,7 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                                "default-accel", accel,
                                                "connect-accel", TRUE,
                                                "accel-editable", FALSE,
-                                               NULL);
+                                               nullptr);
         g_free (accel);
         g_free (action_id);
     }
@@ -708,39 +708,39 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
     for (i = 1; i < 10; ++i)
     {
         char *action_id = g_strdup_printf (MOO_EDIT_GOTO_BOOKMARK_ACTION "%u", i);
-        moo_window_class_new_action_custom (window_class, action_id, NULL,
+        moo_window_class_new_action_custom (window_class, action_id, nullptr,
                                             create_goto_bookmark_action,
                                             GUINT_TO_POINTER (i),
-                                            NULL);
+                                            nullptr);
         g_free (action_id);
     }
 
-    moo_window_class_new_action (window_class, "ToggleBookmark", NULL,
+    moo_window_class_new_action (window_class, "ToggleBookmark", nullptr,
                                  "display-name", _("Toggle Bookmark"),
                                  "label", _("Toggle _Bookmark"),
                                  "stock-id", MOO_STOCK_EDIT_BOOKMARK,
                                  "default-accel", MOO_EDIT_ACCEL_BOOKMARK,
                                  "closure-callback", action_toggle_bookmark,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "NextBookmark", NULL,
+    moo_window_class_new_action (window_class, "NextBookmark", nullptr,
                                  "display-name", _("Next Bookmark"),
                                  "label", _("_Next Bookmark"),
                                  "default-accel", MOO_EDIT_ACCEL_NEXT_BOOKMARK,
                                  "connect-accel", TRUE,
                                  "closure-callback", action_next_bookmark,
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "PreviousBookmark", NULL,
+    moo_window_class_new_action (window_class, "PreviousBookmark", nullptr,
                                  "display-name", _("Previous Bookmark"),
                                  "label", _("_Previous Bookmark"),
                                  "default-accel", MOO_EDIT_ACCEL_PREV_BOOKMARK,
                                  "connect-accel", TRUE,
                                  "closure-callback", action_prev_bookmark,
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Comment", NULL,
+    moo_window_class_new_action (window_class, "Comment", nullptr,
                                  /* action */
                                  "display-name", _("Comment"),
                                  "label", _("Comment"),
@@ -748,9 +748,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-callback", moo_edit_comment_selection,
                                  "closure-proxy-func", moo_edit_window_get_active_doc,
                                  "condition::sensitive", "has-comments",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Uncomment", NULL,
+    moo_window_class_new_action (window_class, "Uncomment", nullptr,
                                  /* action */
                                  "display-name", _("Uncomment"),
                                  "label", _("Uncomment"),
@@ -758,9 +758,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-callback", moo_edit_uncomment_selection,
                                  "closure-proxy-func", moo_edit_window_get_active_doc,
                                  "condition::sensitive", "has-comments",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Indent", NULL,
+    moo_window_class_new_action (window_class, "Indent", nullptr,
                                  "display-name", GTK_STOCK_INDENT,
                                  "label", GTK_STOCK_INDENT,
                                  "tooltip", GTK_STOCK_INDENT,
@@ -768,9 +768,9 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-callback", moo_text_view_indent,
                                  "closure-proxy-func", moo_edit_window_get_active_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Unindent", NULL,
+    moo_window_class_new_action (window_class, "Unindent", nullptr,
                                  "display-name", GTK_STOCK_UNINDENT,
                                  "label", GTK_STOCK_UNINDENT,
                                  "tooltip", GTK_STOCK_UNINDENT,
@@ -778,35 +778,35 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "closure-callback", moo_text_view_unindent,
                                  "closure-proxy-func", moo_edit_window_get_active_view,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "NoDocuments", NULL,
+    moo_window_class_new_action (window_class, "NoDocuments", nullptr,
                                  /* Insensitive menu item which appears in Window menu with no documents open */
                                  "label", _("No Documents"),
                                  "no-accel", TRUE,
                                  "sensitive", FALSE,
                                  "condition::visible", "!has-open-document",
-                                 NULL);
+                                 nullptr);
 
 #ifdef ENABLE_PRINTING
-    moo_window_class_new_action (window_class, "PageSetup", NULL,
+    moo_window_class_new_action (window_class, "PageSetup", nullptr,
                                  "display-name", _("Page Setup"),
                                  "label", _("Page S_etup..."),
                                  "tooltip", _("Page Setup..."),
                                  "default-accel", MOO_EDIT_ACCEL_PAGE_SETUP,
                                  "closure-callback", action_page_setup,
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "PrintPreview", NULL,
+    moo_window_class_new_action (window_class, "PrintPreview", nullptr,
                                  "display-name", GTK_STOCK_PRINT_PREVIEW,
                                  "label", GTK_STOCK_PRINT_PREVIEW,
                                  "tooltip", GTK_STOCK_PRINT_PREVIEW,
                                  "stock-id", GTK_STOCK_PRINT_PREVIEW,
                                  "closure-callback", action_print_preview,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "Print", NULL,
+    moo_window_class_new_action (window_class, "Print", nullptr,
                                  "display-name", GTK_STOCK_PRINT,
                                  "label", _("Print..."),
                                  "tooltip", _("Print..."),
@@ -814,21 +814,21 @@ moo_edit_window_class_init (MooEditWindowClass *klass)
                                  "stock-id", GTK_STOCK_PRINT,
                                  "closure-callback", action_print,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 
-    moo_window_class_new_action (window_class, "PrintPdf", NULL,
+    moo_window_class_new_action (window_class, "PrintPdf", nullptr,
                                  "display-name", _("Export as PDF"),
                                  "label", _("E_xport as PDF..."),
                                  "tooltip", _("Export as PDF..."),
                                  "stock-id", GTK_STOCK_PRINT,
                                  "closure-callback", action_print_pdf,
                                  "condition::sensitive", "has-open-document",
-                                 NULL);
+                                 nullptr);
 #endif
 
-    moo_window_class_new_action_custom (window_class, LANG_ACTION_ID, NULL,
+    moo_window_class_new_action_custom (window_class, LANG_ACTION_ID, nullptr,
                                         (MooWindowActionFunc) create_lang_action,
-                                        NULL, NULL);
+                                        nullptr, nullptr);
 
     {
         GValue val = { 0 };
@@ -845,14 +845,14 @@ moo_edit_window_init (MooEditWindow *window)
     window->priv = G_TYPE_INSTANCE_GET_PRIVATE (window, MOO_TYPE_EDIT_WINDOW, MooEditWindowPrivate);
     new(window->priv) MooEditWindowPrivate;
 
-    window->priv->history = NULL;
+    window->priv->history = nullptr;
     window->priv->history_blocked = FALSE;
     window->priv->enable_history = TRUE;
 
     g_object_set (G_OBJECT (window),
                   "menubar-ui-name", "Editor/Menubar",
                   "toolbar-ui-name", "Editor/Toolbar",
-                  NULL);
+                  nullptr);
 
     set_title_format_from_prefs (window);
 
@@ -866,7 +866,7 @@ moo_edit_window_init (MooEditWindow *window)
 MooEditor *
 moo_edit_window_get_editor (MooEditWindow *window)
 {
-    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);
+    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), nullptr);
     return window->priv->editor;
 }
 
@@ -893,14 +893,14 @@ moo_edit_window_destroy (GtkObject *object)
         GSList *list, *l;
 
         moo_edit_window_abort_jobs (window);
-        g_slist_foreach (window->priv->jobs, (GFunc) g_free, NULL);
+        g_slist_foreach (window->priv->jobs, (GFunc) g_free, nullptr);
         g_slist_free (window->priv->jobs);
-        window->priv->jobs = NULL;
+        window->priv->jobs = nullptr;
 
         list = g_slist_copy (window->priv->stop_clients);
-        for (l = list; l != NULL; l = l->next)
+        for (l = list; l != nullptr; l = l->next)
             moo_edit_window_remove_stop_client (window, (GObject*) l->data);
-        g_assert (window->priv->stop_clients == NULL);
+        g_assert (window->priv->stop_clients == nullptr);
         g_slist_free (list);
     }
 
@@ -977,13 +977,13 @@ static void     moo_edit_window_get_property(GObject        *object,
             break;
         case PROP_HAS_COMMENTS:
             doc = ACTIVE_DOC (window);
-            g_value_set_boolean (value, doc && _moo_edit_has_comments (doc, NULL, NULL));
+            g_value_set_boolean (value, doc && _moo_edit_has_comments (doc, nullptr, nullptr));
             break;
         case PROP_HAS_JOBS_RUNNING:
-            g_value_set_boolean (value, window->priv->jobs != NULL);
+            g_value_set_boolean (value, window->priv->jobs != nullptr);
             break;
         case PROP_HAS_STOP_CLIENTS:
-            g_value_set_boolean (value, window->priv->stop_clients != NULL);
+            g_value_set_boolean (value, window->priv->stop_clients != nullptr);
             break;
 
         default:
@@ -1010,7 +1010,7 @@ moo_edit_window_constructor (GType                  type,
             G_OBJECT_CLASS(moo_edit_window_parent_class)->constructor (type, n_props, props);
 
     window = MOO_EDIT_WINDOW (object);
-    g_return_val_if_fail (window->priv->editor != NULL, object);
+    g_return_val_if_fail (window->priv->editor != nullptr, object);
 
     group = gtk_window_group_new ();
     gtk_window_group_add_window (group, GTK_WINDOW (window));
@@ -1031,7 +1031,7 @@ moo_edit_window_constructor (GType                  type,
                           "show-tabs", TRUE,
                           "enable-popup", TRUE,
                           "enable-reordering", TRUE,
-                          (const char*) NULL));
+                          (const char*) nullptr));
 
         if (i == 0)
             gtk_widget_show (notebook);
@@ -1048,11 +1048,11 @@ moo_edit_window_constructor (GType                  type,
 
     create_statusbar (window);
 
-    g_signal_connect (window, "realize", G_CALLBACK (update_window_title), NULL);
+    g_signal_connect (window, "realize", G_CALLBACK (update_window_title), nullptr);
     g_signal_connect (window, "notify::menubar",
-                      G_CALLBACK (moo_edit_window_connect_menubar), NULL);
+                      G_CALLBACK (moo_edit_window_connect_menubar), nullptr);
 
-    edit_changed (window, NULL);
+    edit_changed (window, nullptr);
     moo_edit_window_check_actions (window);
 
     return object;
@@ -1122,7 +1122,7 @@ parse_title_format(const std::string& format, MooEdit *doc)
 {
     GString *str;
 
-    str = g_string_new (NULL);
+    str = g_string_new (nullptr);
 
     for (const char* p = format.c_str(); *p; )
     {
@@ -1205,7 +1205,7 @@ update_window_title (MooEditWindow *window)
     if (doc)
         title = parse_title_format (window->priv->title_format, doc);
     else
-        title = parse_title_format (window->priv->title_format_no_doc, NULL);
+        title = parse_title_format (window->priv->title_format_no_doc, nullptr);
 
     moo_window_set_title (MOO_WINDOW (window), title.c_str());
 }
@@ -1216,7 +1216,7 @@ check_format (const std::string& format)
     if (format.empty())
         return DEFAULT_TITLE_FORMAT;
 
-    if (!g_utf8_validate (format.c_str(), -1, NULL))
+    if (!g_utf8_validate (format.c_str(), -1, nullptr))
     {
         g_critical ("window title format is not valid UTF8");
         return DEFAULT_TITLE_FORMAT;
@@ -1318,7 +1318,7 @@ action_open (MooEditWindow *window)
     MooEdit *active = moo_edit_window_get_active_doc (window);
     MooOpenInfoArray *files = _moo_edit_open_dialog (GTK_WIDGET (window), active);
     if (!moo_open_info_array_is_empty (files))
-        moo_editor_open_files (window->priv->editor, files, GTK_WIDGET (window), NULL);
+        moo_editor_open_files (window->priv->editor, files, GTK_WIDGET (window), nullptr);
     moo_open_info_array_free (files);
 }
 
@@ -1327,8 +1327,8 @@ static void
 action_reload (MooEditWindow *window)
 {
     MooEdit *doc = ACTIVE_DOC (window);
-    g_return_if_fail (doc != NULL);
-    moo_edit_reload (doc, NULL, NULL);
+    g_return_if_fail (doc != nullptr);
+    moo_edit_reload (doc, nullptr, nullptr);
 }
 
 
@@ -1341,10 +1341,10 @@ reopen_encoding_item_activated (const char *encoding,
     MooReloadInfo *info;
 
     doc = ACTIVE_DOC (window);
-    g_return_if_fail (doc != NULL);
+    g_return_if_fail (doc != nullptr);
 
     info = moo_reload_info_new (encoding, -1);
-    moo_edit_reload (doc, info, NULL);
+    moo_edit_reload (doc, info, nullptr);
 }
 
 static GtkAction *
@@ -1374,7 +1374,7 @@ update_doc_encoding_item (MooEditWindow *window)
         return;
 
     action = moo_window_get_action (MOO_WINDOW (window), "EncodingMenu");
-    g_return_if_fail (action != NULL);
+    g_return_if_fail (action != nullptr);
 
     enc = moo_edit_get_encoding (doc);
 
@@ -1392,7 +1392,7 @@ doc_encoding_item_activated (const char *encoding,
     MooEdit *doc;
 
     doc = ACTIVE_DOC (window);
-    g_return_if_fail (doc != NULL);
+    g_return_if_fail (doc != nullptr);
 
     moo_edit_set_encoding (doc, encoding);
 }
@@ -1414,7 +1414,7 @@ create_doc_encoding_action (MooEditWindow *window)
 
 
 static const char *line_end_menu_items[] = {
-    NULL, /* MOO_LE_NONE */
+    nullptr, /* MOO_LE_NONE */
     "LineEndUnix", /* MOO_LE_UNIX */
     "LineEndWin32", /* MOO_LE_WIN32 */
     "LineEndMac", /* MOO_LE_MAC */
@@ -1431,7 +1431,7 @@ update_doc_line_end_item (MooEditWindow *window)
         return;
 
     action = moo_window_get_action (MOO_WINDOW (window), "LineEndMenu");
-    g_return_if_fail (action != NULL);
+    g_return_if_fail (action != nullptr);
 
     le = moo_edit_get_line_end_type (doc);
     g_return_if_fail (le > 0 && le < G_N_ELEMENTS(line_end_menu_items));
@@ -1446,7 +1446,7 @@ doc_line_end_item_set_active (MooEditWindow *window, gpointer data)
     MooEdit *doc;
 
     doc = ACTIVE_DOC (window);
-    g_return_if_fail (doc != NULL);
+    g_return_if_fail (doc != nullptr);
 
     moo_edit_set_line_end_type (doc, (MooLineEndType) GPOINTER_TO_INT (data));
 }
@@ -1462,23 +1462,23 @@ create_doc_line_end_action (MooEditWindow *window)
 
     g_signal_connect_swapped (mgr, "radio-set-active", G_CALLBACK (doc_line_end_item_set_active), window);
 
-    moo_menu_mgr_append (mgr, NULL,
+    moo_menu_mgr_append (mgr, nullptr,
                          line_end_menu_items[MOO_LE_WIN32],
-                         _("_Windows (CR+LF)"), NULL, MOO_MENU_ITEM_RADIO,
-                         GINT_TO_POINTER (MOO_LE_WIN32), NULL);
-    moo_menu_mgr_insert (mgr, NULL,
+                         _("_Windows (CR+LF)"), nullptr, MOO_MENU_ITEM_RADIO,
+                         GINT_TO_POINTER (MOO_LE_WIN32), nullptr);
+    moo_menu_mgr_insert (mgr, nullptr,
 #ifdef MOO_OS_WIN32
                          1,
 #else
                          0,
 #endif
                          line_end_menu_items[MOO_LE_UNIX],
-                         _("_Unix (LF)"), NULL, MOO_MENU_ITEM_RADIO,
-                         GINT_TO_POINTER (MOO_LE_UNIX), NULL);
-    moo_menu_mgr_append (mgr, NULL,
+                         _("_Unix (LF)"), nullptr, MOO_MENU_ITEM_RADIO,
+                         GINT_TO_POINTER (MOO_LE_UNIX), nullptr);
+    moo_menu_mgr_append (mgr, nullptr,
                          line_end_menu_items[MOO_LE_MAC],
-                         _("_Mac (CR)"), NULL, MOO_MENU_ITEM_RADIO,
-                         GINT_TO_POINTER (MOO_LE_MAC), NULL);
+                         _("_Mac (CR)"), nullptr, MOO_MENU_ITEM_RADIO,
+                         GINT_TO_POINTER (MOO_LE_MAC), nullptr);
 
     moo_bind_bool_property (action, "sensitive",
                             window, "has-open-document", FALSE);
@@ -1491,8 +1491,8 @@ static void
 action_save (MooEditWindow *window)
 {
     MooEdit *doc = ACTIVE_DOC (window);
-    g_return_if_fail (doc != NULL);
-    moo_editor_save (window->priv->editor, doc, NULL);
+    g_return_if_fail (doc != nullptr);
+    moo_editor_save (window->priv->editor, doc, nullptr);
 }
 
 
@@ -1500,8 +1500,8 @@ static void
 action_save_as (MooEditWindow *window)
 {
     MooEdit *doc = ACTIVE_DOC (window);
-    g_return_if_fail (doc != NULL);
-    moo_editor_save_as (window->priv->editor, doc, NULL, NULL);
+    g_return_if_fail (doc != nullptr);
+    moo_editor_save_as (window->priv->editor, doc, nullptr, nullptr);
 }
 
 
@@ -1509,7 +1509,7 @@ static void
 action_close_tab (MooEditWindow *window)
 {
     MooEdit *doc = ACTIVE_DOC (window);
-    g_return_if_fail (doc != NULL);
+    g_return_if_fail (doc != nullptr);
     moo_editor_close_doc (window->priv->editor, doc);
 }
 
@@ -1641,7 +1641,7 @@ moo_edit_window_find_now (MooEditWindow *window,
     MooEditView *view;
 
     view = ACTIVE_VIEW (window);
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
 
     g_signal_emit_by_name (view, "find-word-at-cursor", forward);
 }
@@ -1666,7 +1666,7 @@ action_focus_doc (MooEditWindow *window)
     MooEditView *active_view;
 
     active_view = ACTIVE_VIEW (window);
-    g_return_if_fail (active_view != NULL);
+    g_return_if_fail (active_view != nullptr);
 
     if (!GTK_WIDGET_HAS_FOCUS (active_view))
     {
@@ -1724,7 +1724,7 @@ static void
 action_toggle_bookmark (MooEditWindow *window)
 {
     MooEditView *view = ACTIVE_VIEW (window);
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
     moo_edit_toggle_bookmark (moo_edit_view_get_doc (view),
                               moo_text_view_get_cursor_line (GTK_TEXT_VIEW (view)));
 }
@@ -1738,7 +1738,7 @@ action_next_bookmark (MooEditWindow *window)
     MooEditView *view = ACTIVE_VIEW (window);
     MooEdit *doc = moo_edit_view_get_doc (view);
 
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
 
     cursor = moo_text_view_get_cursor_line (GTK_TEXT_VIEW (view));
     bookmarks = moo_edit_get_bookmarks_in_range (doc, cursor + 1, -1);
@@ -1755,11 +1755,11 @@ static void
 action_prev_bookmark (MooEditWindow *window)
 {
     int cursor;
-    GSList *bookmarks = NULL;
+    GSList *bookmarks = nullptr;
     MooEditView *view = ACTIVE_VIEW (window);
     MooEdit *doc = moo_edit_view_get_doc (view);
 
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
 
     cursor = moo_text_view_get_cursor_line (GTK_TEXT_VIEW (view));
 
@@ -1785,10 +1785,10 @@ goto_bookmark_activated (GtkAction *action,
     guint n = GPOINTER_TO_UINT (data);
 
     window = (MooEditWindow*) _moo_action_get_window (action);
-    g_return_if_fail (window != NULL);
+    g_return_if_fail (window != nullptr);
 
     view = ACTIVE_VIEW (window);
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
 
     if ((bk = moo_edit_get_bookmark (moo_edit_view_get_doc (view), n)))
         moo_edit_view_goto_bookmark (view, bk);
@@ -1808,7 +1808,7 @@ create_goto_bookmark_action (MooWindow *window,
 
     action = GTK_ACTION (g_object_new (MOO_TYPE_ACTION, "name", name, "default-accel", accel,
                                        "connect-accel", TRUE, "accel-editable", FALSE,
-                                       (const char*) NULL));
+                                       (const char*) nullptr));
     g_signal_connect (action, "activate", G_CALLBACK (goto_bookmark_activated), data);
     moo_bind_bool_property (action, "sensitive", window, "has-open-document", FALSE);
 
@@ -1839,7 +1839,7 @@ create_bookmark_item (MooEditWindow   *window,
                       MooEditBookmark *bk)
 {
     char *label, *bk_text;
-    GtkWidget *item = NULL;
+    GtkWidget *item = nullptr;
     MooEdit *doc = moo_edit_view_get_doc (view);
 
     bk_text = _moo_edit_bookmark_get_text (bk);
@@ -1857,7 +1857,7 @@ create_bookmark_item (MooEditWindow   *window,
 
         if (action)
         {
-            g_object_set (action, "label", label, "use-underline", FALSE, NULL);
+            g_object_set (action, "label", label, "use-underline", FALSE, nullptr);
             item = gtk_action_create_menu_item (action);
         }
         else
@@ -1871,7 +1871,7 @@ create_bookmark_item (MooEditWindow   *window,
     if (!item)
     {
         item = gtk_menu_item_new_with_label (label);
-        g_signal_connect (item, "activate", G_CALLBACK (bookmark_item_activated), NULL);
+        g_signal_connect (item, "activate", G_CALLBACK (bookmark_item_activated), nullptr);
     }
 
     widget_bookmark.set(item, g::object_ref (bk), g_object_unref);
@@ -1900,7 +1900,7 @@ populate_bookmark_menu (MooEditWindow *window,
     pos = g_list_index (children, next_bk_item);
     g_return_if_fail (pos >= 0);
 
-    for (l = g_list_nth (children, pos + 1); l != NULL; l = l->next)
+    for (l = g_list_nth (children, pos + 1); l != nullptr; l = l->next)
     {
         if (g_object_get_data ((GObject*) l->data, "moo-bookmark-menu-item"))
             gtk_container_remove (GTK_CONTAINER (menu), (GtkWidget*) l->data);
@@ -1911,13 +1911,13 @@ populate_bookmark_menu (MooEditWindow *window,
     g_list_free (children);
 
     view = ACTIVE_VIEW (window);
-    doc = view ? moo_edit_view_get_doc (view) : NULL;
-    bookmarks = doc ? moo_edit_list_bookmarks (doc) : NULL;
+    doc = view ? moo_edit_view_get_doc (view) : nullptr;
+    bookmarks = doc ? moo_edit_list_bookmarks (doc) : nullptr;
 
     pn = moo_window_get_action (MOO_WINDOW (window), "PreviousBookmark");
-    gtk_action_set_sensitive (pn, bookmarks != NULL);
+    gtk_action_set_sensitive (pn, bookmarks != nullptr);
     pn = moo_window_get_action (MOO_WINDOW (window), "NextBookmark");
-    gtk_action_set_sensitive (pn, bookmarks != NULL);
+    gtk_action_set_sensitive (pn, bookmarks != nullptr);
 
     if (bookmarks)
     {
@@ -1948,7 +1948,7 @@ doc_item_selected (MooWindow   *window,
     next_bk_item = moo_ui_xml_get_widget (moo_window_get_ui_xml (window),
                                           window->menubar,
                                           "Editor/Menubar/Document/NextBookmark");
-    g_return_if_fail (menu != NULL && next_bk_item != NULL);
+    g_return_if_fail (menu != nullptr && next_bk_item != nullptr);
 
     populate_bookmark_menu (MOO_EDIT_WINDOW (window), menu, next_bk_item);
 }
@@ -1966,7 +1966,7 @@ moo_edit_window_connect_menubar (MooWindow *window)
     doc_item = moo_ui_xml_get_widget (moo_window_get_ui_xml (window),
                                       window->menubar,
                                       "Editor/Menubar/Document");
-    g_return_if_fail (doc_item != NULL);
+    g_return_if_fail (doc_item != nullptr);
     g_signal_connect_swapped (doc_item, "select",
                               G_CALLBACK (doc_item_selected),
                               window);
@@ -1974,7 +1974,7 @@ moo_edit_window_connect_menubar (MooWindow *window)
     win_item = moo_ui_xml_get_widget (moo_window_get_ui_xml (window),
                                       window->menubar,
                                       "Editor/Menubar/Window");
-    g_return_if_fail (win_item != NULL);
+    g_return_if_fail (win_item != nullptr);
     g_signal_connect_swapped (win_item, "select",
                               G_CALLBACK (window_menu_item_selected),
                               window);
@@ -1993,7 +1993,7 @@ static void
 action_print (MooEditWindow *window)
 {
     MooEditView *view = ACTIVE_VIEW (window);
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
     _moo_edit_print (GTK_TEXT_VIEW (view), GTK_WIDGET (window));
 }
 
@@ -2002,7 +2002,7 @@ static void
 action_print_preview (MooEditWindow *window)
 {
     MooEditView *view = ACTIVE_VIEW (window);
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
     _moo_edit_print_preview (GTK_TEXT_VIEW (view), GTK_WIDGET (window));
 }
 
@@ -2014,9 +2014,9 @@ action_print_pdf (MooEditWindow *window)
     const char *doc_name, *dot;
     const char *filename;
     MooEditView *view = ACTIVE_VIEW (window);
-    MooEdit *doc = view ? moo_edit_view_get_doc (view) : NULL;
+    MooEdit *doc = view ? moo_edit_view_get_doc (view) : nullptr;
 
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
 
     doc_name = doc ? moo_edit_get_display_basename (doc) : "output";
     dot = strrchr (doc_name, '.');
@@ -2037,7 +2037,7 @@ action_print_pdf (MooEditWindow *window)
                                  start_name,
                                  _("Export as PDF"),
                                  moo_edit_setting (MOO_EDIT_PREFS_PDF_LAST_DIR),
-                                 NULL);
+                                 nullptr);
 
     if (filename)
         _moo_edit_export_pdf (GTK_TEXT_VIEW (view), filename);
@@ -2052,7 +2052,7 @@ wrap_text_toggled (MooEditWindow *window,
                    gboolean       active)
 {
     MooEditView *view = ACTIVE_VIEW (window);
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
     _moo_edit_view_ui_set_line_wrap (view, active);
 }
 
@@ -2062,7 +2062,7 @@ line_numbers_toggled (MooEditWindow *window,
                       gboolean       active)
 {
     MooEditView *view = ACTIVE_VIEW (window);
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
     _moo_edit_view_ui_set_show_line_numbers (view, active);
 }
 
@@ -2111,7 +2111,7 @@ detach_activated (GtkWidget     *item,
     g_return_if_fail (MOO_IS_EDIT_WINDOW (window));
     g_return_if_fail (MOO_IS_EDIT (doc));
 
-    _moo_editor_move_doc (window->priv->editor, doc, NULL, NULL, TRUE);
+    _moo_editor_move_doc (window->priv->editor, doc, nullptr, nullptr, TRUE);
 }
 
 
@@ -2126,7 +2126,7 @@ move_to_split_notebook_activated (GtkWidget     *item,
 
 static void
 copy_full_path_activated (GtkWidget     *item,
-                          MooEditWindow *window)
+                          G_GNUC_UNUSED MooEditWindow *window)
 {
     MooEdit *doc = widget_doc.get(item);
     GtkClipboard *clipboard = gtk_widget_get_clipboard(item, GDK_SELECTION_CLIPBOARD);
@@ -2135,8 +2135,8 @@ copy_full_path_activated (GtkWidget     *item,
 
 
 static void
-open_containing_folder_activated (GtkWidget     *item,
-                                  MooEditWindow *window)
+open_containing_folder_activated (G_GNUC_UNUSED GtkWidget     *item,
+                                  G_GNUC_UNUSED MooEditWindow *window)
 {
 }
 
@@ -2207,7 +2207,7 @@ move_tab_to_split_view (MooEditWindow *window,
 
     g_object_ref (tab);
 
-    window->priv->active_tab = NULL;
+    window->priv->active_tab = nullptr;
 
     gtk_container_remove (GTK_CONTAINER (old_nb), GTK_WIDGET (tab));
     label = create_tab_label (window, tab, doc);
@@ -2271,7 +2271,7 @@ add_separator (GtkMenu  *menu)
     gtk_menu_shell_append(GTK_MENU_SHELL(menu),
                           GTK_WIDGET(g_object_new(GTK_TYPE_SEPARATOR_MENU_ITEM,
                                                   "visible", TRUE,
-                                                  (const char*) NULL)));
+                                                  (const char*) nullptr)));
 }
 
 static gboolean
@@ -2367,9 +2367,9 @@ set_use_tabs (MooEditWindow *window,
               MooNotebook   *notebook)
 {
     g_return_if_fail (MOO_IS_EDIT_WINDOW (window));
-    g_return_if_fail (notebook != NULL);
+    g_return_if_fail (notebook != nullptr);
     g_object_set (notebook, "show-tabs",
-                  moo_prefs_get_bool (moo_edit_setting (MOO_EDIT_PREFS_USE_TABS)), NULL);
+                  moo_prefs_get_bool (moo_edit_setting (MOO_EDIT_PREFS_USE_TABS)), nullptr);
 }
 
 void
@@ -2388,7 +2388,7 @@ static MooNotebook *
 get_notebook (MooEditWindow *window,
               int            i)
 {
-    g_return_val_if_fail (i >= 0 && i < (int) window->priv->notebooks.size(), NULL);
+    g_return_val_if_fail (i >= 0 && i < (int) window->priv->notebooks.size(), nullptr);
     return window->priv->notebooks[i].get();
 }
 
@@ -2398,12 +2398,12 @@ get_notebook_active_view (MooNotebook *notebook)
     GtkWidget *tab;
     int page;
 
-    g_return_val_if_fail (notebook != NULL, NULL);
+    g_return_val_if_fail (notebook != nullptr, nullptr);
 
     page = moo_notebook_get_current_page (notebook);
 
     if (page < 0)
-        return NULL;
+        return nullptr;
 
     tab = moo_notebook_get_nth_page (notebook, page);
     return moo_edit_tab_get_active_view (MOO_EDIT_TAB (tab));
@@ -2413,7 +2413,7 @@ static MooEdit *
 get_notebook_active_doc (MooNotebook *notebook)
 {
     MooEditView *view = get_notebook_active_view (notebook);
-    return view ? moo_edit_view_get_doc (view) : NULL;
+    return view ? moo_edit_view_get_doc (view) : nullptr;
 }
 
 static MooNotebook *
@@ -2424,8 +2424,8 @@ get_active_notebook (MooEditWindow *window)
     nb1 = get_notebook (window, 0);
     nb2 = get_notebook (window, 1);
 
-    g_return_val_if_fail (nb2 != NULL, nb1);
-    g_return_val_if_fail (nb1 != NULL, nb2);
+    g_return_val_if_fail (nb2 != nullptr, nb1);
+    g_return_val_if_fail (nb1 != nullptr, nb2);
 
     if (!GTK_WIDGET_VISIBLE (nb2))
         return nb1;
@@ -2485,7 +2485,7 @@ notebook_close_button_clicked (GtkWidget     *button,
                                MooEditWindow *window)
 {
     MooNotebook *notebook = data_notebook.get(button);
-    g_return_if_fail (notebook != NULL);
+    g_return_if_fail (notebook != nullptr);
     moo_editor_close_doc (window->priv->editor, get_notebook_active_doc (notebook));
 }
 
@@ -2504,7 +2504,7 @@ setup_notebook (MooEditWindow *window,
     g_signal_connect (notebook, "button-press-event",
                       G_CALLBACK (notebook_button_press), window);
 
-    frame = gtk_aspect_frame_new (NULL, 0.5, 0.5, 1.0, FALSE);
+    frame = gtk_aspect_frame_new (nullptr, 0.5, 0.5, 1.0, FALSE);
     gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_NONE);
 
     button = gtk_button_new ();
@@ -2621,9 +2621,9 @@ view_wrap_mode_changed (MooEditWindow *window,
         return;
 
     action = moo_window_get_action (MOO_WINDOW (window), "WrapText");
-    g_return_if_fail (action != NULL);
+    g_return_if_fail (action != nullptr);
 
-    g_object_get (view, "wrap-mode", &mode, NULL);
+    g_object_get (view, "wrap-mode", &mode, nullptr);
     gtk_toggle_action_set_active (GTK_TOGGLE_ACTION (action), mode != GTK_WRAP_NONE);
 
     /* XXX menu item and action go out of sync for some reason */
@@ -2643,9 +2643,9 @@ view_show_line_numbers_changed (MooEditWindow *window,
         return;
 
     action = moo_window_get_action (MOO_WINDOW (window), "LineNumbers");
-    g_return_if_fail (action != NULL);
+    g_return_if_fail (action != nullptr);
 
-    g_object_get (view, "show-line-numbers", &show, NULL);
+    g_object_get (view, "show-line-numbers", &show, nullptr);
     gtk_toggle_action_set_active (GTK_TOGGLE_ACTION (action), show);
 
     /* XXX menu item and action go out of sync for some reason */
@@ -2663,8 +2663,8 @@ update_doc_view_actions (MooEditWindow *window)
     if (!view)
         return;
 
-    view_wrap_mode_changed (window, NULL, view);
-    view_show_line_numbers_changed (window, NULL, view);
+    view_wrap_mode_changed (window, nullptr, view);
+    view_show_line_numbers_changed (window, nullptr, view);
 }
 
 
@@ -2694,7 +2694,7 @@ MooEdit *
 moo_edit_window_get_active_doc (MooEditWindow  *window)
 {
     MooEditView *view = moo_edit_window_get_active_view (window);
-    return view ? moo_edit_view_get_doc (view) : NULL;
+    return view ? moo_edit_view_get_doc (view) : nullptr;
 }
 
 /**
@@ -2704,7 +2704,7 @@ MooEditView *
 moo_edit_window_get_active_view (MooEditWindow *window)
 {
     MooEditTab *tab = moo_edit_window_get_active_tab (window);
-    return tab ? moo_edit_tab_get_active_view (tab) : NULL;
+    return tab ? moo_edit_tab_get_active_view (tab) : nullptr;
 }
 
 /**
@@ -2713,10 +2713,10 @@ moo_edit_window_get_active_view (MooEditWindow *window)
 MooEditTab *
 moo_edit_window_get_active_tab (MooEditWindow *window)
 {
-    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);
+    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), nullptr);
 
     if (window->priv->notebooks.empty())
-        return NULL;
+        return nullptr;
 
     if (!window->priv->active_tab)
     {
@@ -2724,12 +2724,12 @@ moo_edit_window_get_active_tab (MooEditWindow *window)
         int page;
         MooNotebook *notebook = get_active_notebook (window);
 
-        g_return_val_if_fail (notebook != NULL, NULL);
+        g_return_val_if_fail (notebook != nullptr, nullptr);
 
         page = moo_notebook_get_current_page (notebook);
 
         if (page < 0)
-            return NULL;
+            return nullptr;
 
         tab = moo_notebook_get_nth_page (notebook, page);
         window->priv->active_tab = MOO_EDIT_TAB (tab);
@@ -2758,7 +2758,7 @@ moo_edit_window_set_active_doc (MooEditWindow *window,
         guint i;
         MooEditViewArray *views;
 
-        view = NULL;
+        view = nullptr;
         views = moo_edit_get_views (doc);
 
         for (i = 0; i < moo_edit_view_array_get_size (views); ++i)
@@ -2774,7 +2774,7 @@ moo_edit_window_set_active_doc (MooEditWindow *window,
         moo_edit_view_array_free (views);
     }
 
-    g_return_if_fail (view != NULL);
+    g_return_if_fail (view != nullptr);
 
     moo_edit_window_set_active_view (window, view);
 }
@@ -2787,7 +2787,7 @@ moo_edit_window_set_active_view (MooEditWindow *window,
                                  MooEditView   *view)
 {
     int page;
-    MooNotebook *notebook = NULL;
+    MooNotebook *notebook = nullptr;
 
     g_return_if_fail (MOO_IS_EDIT_WINDOW (window));
     g_return_if_fail (MOO_IS_EDIT_VIEW (view));
@@ -2824,10 +2824,10 @@ moo_edit_window_get_docs (MooEditWindow *window)
     MooEditArray *docs;
     guint i;
 
-    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);
+    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), nullptr);
 
     tabs = moo_edit_window_get_tabs (window);
-    g_return_val_if_fail (tabs != NULL, NULL);
+    g_return_val_if_fail (tabs != nullptr, nullptr);
 
     docs = moo_edit_array_new ();
 
@@ -2853,7 +2853,7 @@ moo_edit_window_get_views (MooEditWindow *window)
     int inb;
     MooEditViewArray *views;
 
-    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);
+    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), nullptr);
 
     views = moo_edit_view_array_new ();
 
@@ -2885,7 +2885,7 @@ moo_edit_window_get_tabs (MooEditWindow *window)
     int inb;
     MooEditTabArray *tabs;
 
-    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);
+    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), nullptr);
 
     tabs = moo_edit_tab_array_new ();
 
@@ -2924,7 +2924,7 @@ get_nth_doc (MooNotebook *notebook,
              guint        n)
 {
     MooEditTab *tab = get_nth_tab (*notebook, n);
-    return tab ? moo_edit_tab_get_doc (tab) : NULL;
+    return tab ? moo_edit_tab_get_doc (tab) : nullptr;
 }
 
 static MooEditTab *
@@ -2932,7 +2932,7 @@ get_nth_tab (MooNotebook &notebook,
              guint        n)
 {
     GtkWidget *tab = moo_notebook_get_nth_page (&notebook, n);
-    return tab ? MOO_EDIT_TAB (tab) : NULL;
+    return tab ? MOO_EDIT_TAB (tab) : nullptr;
 }
 
 static int
@@ -2941,7 +2941,7 @@ get_active_tab (MooEditWindow *window)
     int tab = 0;
     MooNotebook *notebook = get_active_notebook (window);
 
-    g_return_val_if_fail (notebook != NULL, -1);
+    g_return_val_if_fail (notebook != nullptr, -1);
 
     for (const auto& nb: window->priv->notebooks)
     {
@@ -2983,7 +2983,7 @@ get_view_page_num (MooEditWindow  *window,
     }
 
     if (pnotebook)
-        *pnotebook = NULL;
+        *pnotebook = nullptr;
     return -1;
 }
 
@@ -3068,7 +3068,7 @@ _moo_edit_window_insert_tab (MooEditWindow *window,
     GtkWidget *label;
     MooEdit *doc;
     MooEditViewArray *views;
-    MooNotebook *notebook = NULL;
+    MooNotebook *notebook = nullptr;
     int page = -1;
     guint i;
 
@@ -3141,7 +3141,7 @@ _moo_edit_window_remove_doc (MooEditWindow *window,
     MooEditView *new_view;
     MooEditViewArray *views;
     gboolean had_focus = FALSE;
-    MooNotebook *notebook = NULL;
+    MooNotebook *notebook = nullptr;
     MooEditTab *tab;
     guint i;
 
@@ -3155,10 +3155,10 @@ _moo_edit_window_remove_doc (MooEditWindow *window,
     g_return_if_fail (moo_edit_view_array_get_size (views) > 0);
 
     page = get_view_page_num (window, views->elms[0], &notebook);
-    g_return_if_fail (notebook != NULL && page >= 0);
+    g_return_if_fail (notebook != nullptr && page >= 0);
 
     if (tab == window->priv->active_tab)
-        window->priv->active_tab = NULL;
+        window->priv->active_tab = nullptr;
 
     for (i = 0; i < views->n_elms; ++i)
     {
@@ -3206,7 +3206,7 @@ _moo_edit_window_remove_doc (MooEditWindow *window,
             moo_edit_window_set_active_doc (window, (MooEdit*) window->priv->history->data);
     }
 
-    edit_changed (window, NULL);
+    edit_changed (window, nullptr);
 
     g_signal_emit (window, signals[CLOSE_DOC_AFTER], 0);
 
@@ -3292,7 +3292,7 @@ tab_icon_start_drag (GtkWidget      *evbox,
     g_signal_connect (evbox, "drag-data-get", G_CALLBACK (tab_icon_drag_data_get), window);
     g_signal_connect (evbox, "drag-end", G_CALLBACK (tab_icon_drag_end), window);
 
-    targets = gtk_target_list_new (NULL, 0);
+    targets = gtk_target_list_new (nullptr, 0);
 
     gtk_target_list_add (targets,
                          moo_atom_uri_list (),
@@ -3318,7 +3318,7 @@ tab_icon_motion_notify (GtkWidget      *evbox,
     DragInfo *info;
 
     info = data_drag_info.get(evbox);
-    g_return_val_if_fail (info != NULL, FALSE);
+    g_return_val_if_fail (info != nullptr, FALSE);
 
     if (info->drag_started)
         return TRUE;
@@ -3469,7 +3469,7 @@ create_tab_label (MooEditWindow *window,
             }
         }
 
-        frame = gtk_aspect_frame_new (NULL, 0.5, 0.5, 1.0, FALSE);
+        frame = gtk_aspect_frame_new (nullptr, 0.5, 0.5, 1.0, FALSE);
         gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_NONE);
 
         button = gtk_button_new ();
@@ -3545,7 +3545,7 @@ update_tab_label (MooEditTab    *tab,
     MooEdit *doc;
 
     doc = moo_edit_tab_get_doc (tab);
-    g_return_if_fail (doc != NULL);
+    g_return_if_fail (doc != nullptr);
 
     hbox = moo_notebook_get_tab_label (&notebook, GTK_WIDGET (tab));
     g_return_if_fail (GTK_IS_WIDGET (hbox));
@@ -3626,7 +3626,7 @@ save_paned_config (MooEditWindow *window)
     const char *old_config;
 
     config = moo_big_paned_get_config (window->paned);
-    g_return_if_fail (config != NULL);
+    g_return_if_fail (config != nullptr);
 
     old_config = moo_prefs_get_string (MOO_EDIT_PREFS_PREFIX "/window/paned");
 
@@ -3645,7 +3645,7 @@ create_paned (MooEditWindow *window)
     paned = MOO_BIG_PANED (g_object_new (MOO_TYPE_BIG_PANED,
                                          "handle-cursor-type", GDK_FLEUR,
                                          "enable-detaching", TRUE,
-                                         (const char*) NULL));
+                                         (const char*) nullptr));
     gtk_widget_show (GTK_WIDGET (paned));
     gtk_box_pack_start (GTK_BOX (MOO_WINDOW(window)->vbox),
                         GTK_WIDGET (paned), TRUE, TRUE, 0);
@@ -3653,7 +3653,7 @@ create_paned (MooEditWindow *window)
     window->paned = paned;
 
     moo_prefs_create_key (MOO_EDIT_PREFS_PREFIX "/window/paned",
-                          MOO_PREFS_STATE, G_TYPE_STRING, NULL);
+                          MOO_PREFS_STATE, G_TYPE_STRING, nullptr);
     config = moo_prefs_get_string (MOO_EDIT_PREFS_PREFIX "/window/paned");
 
     if (config)
@@ -3695,7 +3695,7 @@ add_pane_action (MooEditWindow *window,
     {
         guint merge_id;
 
-        _moo_window_class_new_action_callback (klass, action_id, NULL,
+        _moo_window_class_new_action_callback (klass, action_id, nullptr,
                                                G_CALLBACK (show_pane_callback),
                                                _moo_marshal_VOID__STRING,
                                                G_TYPE_NONE, 1,
@@ -3705,7 +3705,7 @@ add_pane_action (MooEditWindow *window,
                                                "label", label->label,
                                                /* XXX IconInfo */
                                                "stock-id", label->icon_stock_id,
-                                               NULL);
+                                               nullptr);
 
         xml = moo_editor_get_ui_xml (moo_editor_instance ());
         merge_id = moo_ui_xml_new_merge_id (xml);
@@ -3715,8 +3715,8 @@ add_pane_action (MooEditWindow *window,
     }
 
     action = moo_window_get_action (MOO_WINDOW (window), action_id);
-    g_return_if_fail (action != NULL);
-    g_object_set (action, "visible", TRUE, NULL);
+    g_return_if_fail (action != nullptr);
+    g_object_set (action, "visible", TRUE, nullptr);
 
     g_free (action_id);
 }
@@ -3732,7 +3732,7 @@ remove_pane_action (MooEditWindow *window,
     action = moo_window_get_action (MOO_WINDOW (window), action_id);
 
     if (action)
-        g_object_set (action, "visible", FALSE, NULL);
+        g_object_set (action, "visible", FALSE, nullptr);
 
 #if 0
     klass = g_type_class_peek (MOO_TYPE_EDIT_WINDOW);
@@ -3754,18 +3754,18 @@ moo_edit_window_add_pane_full (MooEditWindow  *window,
 {
     MooPane *pane;
 
-    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);
-    g_return_val_if_fail (user_id != NULL, NULL);
-    g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);
-    g_return_val_if_fail (label != NULL, NULL);
+    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), nullptr);
+    g_return_val_if_fail (user_id != nullptr, nullptr);
+    g_return_val_if_fail (GTK_IS_WIDGET (widget), nullptr);
+    g_return_val_if_fail (label != nullptr, nullptr);
 
-    g_return_val_if_fail (moo_edit_window_get_pane (window, user_id) == NULL, NULL);
+    g_return_val_if_fail (moo_edit_window_get_pane (window, user_id) == nullptr, nullptr);
 
     g_object_ref_sink (widget);
 
     pane = moo_big_paned_insert_pane (window->paned, widget, user_id, label, position, -1);
 
-    if (pane != NULL)
+    if (pane != nullptr)
     {
         moo_pane_set_removable (pane, FALSE);
 
@@ -3811,7 +3811,7 @@ moo_edit_window_remove_pane (MooEditWindow *window,
     MooPane *pane;
 
     g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), FALSE);
-    g_return_val_if_fail (user_id != NULL, FALSE);
+    g_return_val_if_fail (user_id != nullptr, FALSE);
 
     remove_pane_action (window, user_id);
 
@@ -3838,7 +3838,7 @@ moo_edit_window_show_pane (MooEditWindow *window,
     g_return_if_fail (MOO_IS_EDIT_WINDOW (window));
 
     pane = moo_edit_window_get_pane (window, user_id);
-    g_return_if_fail (pane != NULL);
+    g_return_if_fail (pane != nullptr);
 
     moo_big_paned_present_pane (window->paned, pane);
 }
@@ -3856,11 +3856,11 @@ moo_edit_window_get_pane (MooEditWindow  *window,
 {
     MooPane *pane;
 
-    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);
-    g_return_val_if_fail (user_id != NULL, NULL);
+    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), nullptr);
+    g_return_val_if_fail (user_id != nullptr, nullptr);
 
     pane = moo_big_paned_lookup_pane (window->paned, user_id);
-    return pane ? moo_pane_get_child (pane) : NULL;
+    return pane ? moo_pane_get_child (pane) : nullptr;
 }
 
 
@@ -3950,8 +3950,8 @@ update_statusbar (MooEditWindow *window)
         window->priv->statusbar_idle =
             g_idle_add_full (G_PRIORITY_HIGH,
                              (GSourceFunc) update_statusbar_idle,
-                             window, NULL);
-    moo_window_message (MOO_WINDOW (window), NULL);
+                             window, nullptr);
+    moo_window_message (MOO_WINDOW (window), nullptr);
 }
 
 static void
@@ -3966,7 +3966,7 @@ create_statusbar (MooEditWindow *window)
                                        "pack-type", GTK_PACK_END,
                                        "expand", FALSE,
                                        "fill", FALSE,
-                                       NULL);
+                                       nullptr);
 
     window->priv->cursor_label = xml->cursor;
     window->priv->chars_label = xml->chars;
@@ -3996,7 +3996,7 @@ lang_item_activated (MooEditWindow *window,
     const char *old_val;
     gboolean do_set = FALSE;
 
-    g_return_if_fail (doc != NULL);
+    g_return_if_fail (doc != nullptr);
     g_return_if_fail (MOO_IS_EDIT_WINDOW (window));
 
     old_val = moo_edit_config_get_string (doc->config, "lang");
@@ -4008,7 +4008,7 @@ lang_item_activated (MooEditWindow *window,
 
     if (do_set)
         moo_edit_config_set (doc->config, MOO_EDIT_CONFIG_SOURCE_USER,
-                             "lang", lang_name, NULL);
+                             "lang", lang_name, nullptr);
 }
 
 
@@ -4032,24 +4032,24 @@ create_lang_action (MooEditWindow *window)
     action = moo_menu_action_new (LANG_ACTION_ID, _("_Language"));
     menu_mgr = moo_menu_action_get_mgr (MOO_MENU_ACTION (action));
 
-    moo_menu_mgr_append (menu_mgr, NULL,
+    moo_menu_mgr_append (menu_mgr, nullptr,
                          /* Menu item in the Language menu */
-                         MOO_LANG_NONE, Q_("Language|None"), NULL,
-                         MOO_MENU_ITEM_RADIO, NULL, NULL);
+                         MOO_LANG_NONE, Q_("Language|None"), nullptr,
+                         MOO_MENU_ITEM_RADIO, nullptr, nullptr);
 
-    for (l = sections; l != NULL; l = l->next)
-        moo_menu_mgr_append (menu_mgr, NULL,
-                             (const char*) l->data, (const char*) l->data, NULL,
-                             MOO_MENU_ITEM_FLAGS_NONE, NULL, NULL);
+    for (l = sections; l != nullptr; l = l->next)
+        moo_menu_mgr_append (menu_mgr, nullptr,
+                             (const char*) l->data, (const char*) l->data, nullptr,
+                             MOO_MENU_ITEM_FLAGS_NONE, nullptr, nullptr);
 
-    for (l = langs; l != NULL; l = l->next)
+    for (l = langs; l != nullptr; l = l->next)
     {
         MooLang *lang = (MooLang*) l->data;
         if (!_moo_lang_get_hidden (lang))
             moo_menu_mgr_append (menu_mgr, _moo_lang_get_section (lang),
                                  _moo_lang_id (lang),
                                  _moo_lang_display_name (lang),
-                                 NULL, MOO_MENU_ITEM_RADIO,
+                                 nullptr, MOO_MENU_ITEM_RADIO,
                                  g_strdup (_moo_lang_id (lang)),
                                  g_free);
     }
@@ -4057,9 +4057,9 @@ create_lang_action (MooEditWindow *window)
     g_signal_connect_swapped (menu_mgr, "radio-set-active",
                               G_CALLBACK (lang_item_activated), window);
 
-    g_slist_foreach (langs, (GFunc) g_object_unref, NULL);
+    g_slist_foreach (langs, (GFunc) g_object_unref, nullptr);
     g_slist_free (langs);
-    g_slist_foreach (sections, (GFunc) g_free, NULL);
+    g_slist_foreach (sections, (GFunc) g_free, nullptr);
     g_slist_free (sections);
 
     moo_bind_bool_property (action, "sensitive", window, "has-open-document", FALSE);
@@ -4081,7 +4081,7 @@ update_lang_menu (MooEditWindow      *window)
 
     lang = moo_text_view_get_lang (MOO_TEXT_VIEW (view));
     action = moo_window_get_action (MOO_WINDOW (window), LANG_ACTION_ID);
-    g_return_if_fail (action != NULL);
+    g_return_if_fail (action != nullptr);
 
     moo_menu_mgr_set_active (moo_menu_action_get_mgr (MOO_MENU_ACTION (action)),
                              _moo_lang_id (lang), TRUE);
@@ -4142,7 +4142,7 @@ window_check_one_action (const char    *action_id,
         sensitive = func (action, window, doc, data);
     }
 
-    g_object_set (action, "visible", visible, "sensitive", sensitive, NULL);
+    g_object_set (action, "visible", visible, "sensitive", sensitive, nullptr);
 }
 
 
@@ -4186,9 +4186,9 @@ moo_edit_window_set_action_check (const char     *action_id,
 {
     ActionCheck *check;
 
-    g_return_if_fail (action_id != NULL);
+    g_return_if_fail (action_id != nullptr);
     g_return_if_fail (type < N_ACTION_CHECKS);
-    g_return_if_fail (func != NULL);
+    g_return_if_fail (func != nullptr);
 
     action_checks_init ();
 
@@ -4202,7 +4202,7 @@ moo_edit_window_set_action_check (const char     *action_id,
 
     if (check->checks[type].func)
     {
-        check->checks[type].func = NULL;
+        check->checks[type].func = nullptr;
 
         if (check->checks[type].notify)
             check->checks[type].notify (check->checks[type].data);
@@ -4228,7 +4228,7 @@ moo_edit_window_remove_action_check (const char        *action_id,
     gboolean remove = TRUE;
     guint i;
 
-    g_return_if_fail (action_id != NULL);
+    g_return_if_fail (action_id != nullptr);
     g_return_if_fail (type <= N_ACTION_CHECKS);
 
     if (!action_checks)
@@ -4252,7 +4252,7 @@ moo_edit_window_remove_action_check (const char        *action_id,
 
         if (!remove && check->checks[type].func && check->checks[type].notify)
         {
-            check->checks[type].func = NULL;
+            check->checks[type].func = nullptr;
             check->checks[type].notify (check->checks[type].data);
         }
     }
@@ -4296,9 +4296,9 @@ moo_edit_window_set_action_filter (const char        *action_id,
                                    MooActionCheckType type,
                                    const char        *filter_string)
 {
-    MooEditFilter *filter = NULL;
+    MooEditFilter *filter = nullptr;
 
-    g_return_if_fail (action_id != NULL);
+    g_return_if_fail (action_id != nullptr);
     g_return_if_fail (type < N_ACTION_CHECKS);
 
     if (filter_string && filter_string[0])
@@ -4319,7 +4319,7 @@ action_checks_init (void)
 {
     if (!action_checks)
         action_checks =
-                g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
+                g_hash_table_new_full (g_str_hash, g_str_equal, g_free, nullptr);
 }
 
 
@@ -4413,7 +4413,7 @@ moo_edit_window_add_stop_client (MooEditWindow  *window,
     g_return_if_fail (query.n_params == 0);
 #undef REAL_TYPE
 
-    had_clients = window->priv->stop_clients != NULL;
+    had_clients = window->priv->stop_clients != nullptr;
     window->priv->stop_clients = g_slist_prepend (window->priv->stop_clients, client);
     g_object_weak_ref (client, (GWeakNotify) client_died, window);
     g_signal_connect (client, "job-started", G_CALLBACK (client_job_started), window);
@@ -4460,7 +4460,7 @@ moo_edit_window_abort_jobs (MooEditWindow *window)
 
     jobs = g_slist_copy (window->priv->jobs);
 
-    for (l = jobs; l != NULL; l = l->next)
+    for (l = jobs; l != nullptr; l = l->next)
     {
         Job *j = (Job*) l->data;
         j->abort (j->job);
@@ -4480,14 +4480,14 @@ moo_edit_window_job_started (MooEditWindow  *window,
     gboolean had_jobs;
 
     g_return_if_fail (MOO_IS_EDIT_WINDOW (window));
-    g_return_if_fail (func != NULL);
-    g_return_if_fail (job != NULL);
+    g_return_if_fail (func != nullptr);
+    g_return_if_fail (job != nullptr);
 
     j = g_new0 (Job, 1);
     j->abort = func;
     j->job = job;
 
-    had_jobs = window->priv->jobs != NULL;
+    had_jobs = window->priv->jobs != nullptr;
     window->priv->jobs = g_slist_prepend (window->priv->jobs, j);
 
     if (!had_jobs)
@@ -4500,19 +4500,19 @@ moo_edit_window_job_finished (MooEditWindow  *window,
                               gpointer        job)
 {
     GSList *l;
-    Job *j = NULL;
+    Job *j = nullptr;
 
     g_return_if_fail (MOO_IS_EDIT_WINDOW (window));
-    g_return_if_fail (job != NULL);
+    g_return_if_fail (job != nullptr);
 
-    for (l = window->priv->jobs; l != NULL; l = l->next)
+    for (l = window->priv->jobs; l != nullptr; l = l->next)
     {
         j = (Job*) l->data;
 
         if (j->job == job)
             break;
         else
-            j = NULL;
+            j = nullptr;
     }
 
     if (j)
@@ -4580,7 +4580,7 @@ populate_window_menu (MooEditWindow *window,
     pos = g_list_index (children, no_docs_item);
     g_return_if_fail (pos >= 0);
 
-    for (l = g_list_nth (children, pos + 1); l != NULL; l = l->next)
+    for (l = g_list_nth (children, pos + 1); l != nullptr; l = l->next)
     {
         if (data_is_doc_menu_item.get(GTK_WIDGET (l->data)))
             gtk_container_remove (GTK_CONTAINER (menu), (GtkWidget*) l->data);
@@ -4646,7 +4646,7 @@ window_menu_item_selected (MooWindow   *window,
     no_docs_item = moo_ui_xml_get_widget (moo_window_get_ui_xml (window),
                                           window->menubar,
                                           "Editor/Menubar/Window/NoDocuments");
-    g_return_if_fail (menu != NULL && no_docs_item != NULL);
+    g_return_if_fail (menu != nullptr && no_docs_item != nullptr);
 
     populate_window_menu (MOO_EDIT_WINDOW (window), menu, no_docs_item);
 }
@@ -4697,7 +4697,7 @@ notebook_drag_motion (GtkWidget          *widget,
 {
     GdkAtom target;
 
-    target = gtk_drag_dest_find_target (widget, context, NULL);
+    target = gtk_drag_dest_find_target (widget, context, nullptr);
 
     if (target == GDK_NONE)
         return FALSE;
@@ -4721,7 +4721,7 @@ notebook_drag_drop (GtkWidget          *widget,
 {
     GdkAtom target;
 
-    target = gtk_drag_dest_find_target (widget, context, NULL);
+    target = gtk_drag_dest_find_target (widget, context, nullptr);
 
     if (target == GDK_NONE)
     {
@@ -4756,12 +4756,12 @@ notebook_drag_data_recv (GtkWidget          *widget,
         if (data->target == MOO_EDIT_TAB_ATOM)
         {
             GtkWidget *toplevel;
-            GtkWidget *src_notebook = NULL;
+            GtkWidget *src_notebook = nullptr;
             MooEdit *doc;
             MooEditTab *tab;
 
             tab = (MooEditTab*) moo_selection_data_get_pointer (data, MOO_EDIT_TAB_ATOM);
-            doc = tab ? moo_edit_tab_get_doc (tab) : NULL;
+            doc = tab ? moo_edit_tab_get_doc (tab) : nullptr;
 
             if (!doc)
                 goto out;
@@ -4796,9 +4796,9 @@ notebook_drag_data_recv (GtkWidget          *widget,
 
             for (u = uris; *u; ++u)
             {
-                char *filename = g_filename_from_uri (*u, NULL, NULL);
+                char *filename = g_filename_from_uri (*u, nullptr, nullptr);
                 if (!filename || !g_file_test (filename, G_FILE_TEST_IS_DIR))
-                    moo_editor_open_uri (window->priv->editor, *u, NULL, -1, window);
+                    moo_editor_open_uri (window->priv->editor, *u, nullptr, -1, window);
                 g_free (filename);
             }
 
@@ -4855,7 +4855,7 @@ notebook_drag_data_recv (GtkWidget          *widget,
 
             if (toplevel == GTK_WIDGET (window))
             {
-                GtkWidget *src_notebook = NULL;
+                GtkWidget *src_notebook = nullptr;
                 src_notebook = gtk_widget_get_parent (GTK_WIDGET (tab));
                 g_assert (MOO_IS_NOTEBOOK (widget));
                 can_move = src_notebook != widget;
@@ -4894,7 +4894,7 @@ split_view_horizontal_toggled (MooEditWindow *window,
                                gboolean       active)
 {
     MooEditTab *tab = ACTIVE_TAB (window);
-    g_return_if_fail (tab != NULL);
+    g_return_if_fail (tab != nullptr);
     if (_moo_edit_tab_set_split_horizontal (tab, active))
         update_split_view_actions (window);
 }
@@ -4904,7 +4904,7 @@ split_view_vertical_toggled (MooEditWindow *window,
                              gboolean       active)
 {
     MooEditTab *tab = ACTIVE_TAB (window);
-    g_return_if_fail (tab != NULL);
+    g_return_if_fail (tab != nullptr);
     if (_moo_edit_tab_set_split_vertical (tab, active))
         update_split_view_actions (window);
 }
@@ -4913,7 +4913,7 @@ static void
 action_focus_next_split_view (MooEditWindow *window)
 {
     MooEditTab *tab = ACTIVE_TAB (window);
-    g_return_if_fail (tab != NULL);
+    g_return_if_fail (tab != nullptr);
     _moo_edit_tab_focus_next_view (tab);
     update_doc_view_actions (window);
 }
@@ -4932,11 +4932,11 @@ update_split_view_actions (MooEditWindow *window)
         return;
 
     action_cycle = moo_window_get_action (MOO_WINDOW (window), "CycleSplitViews");
-    g_return_if_fail (action_cycle != NULL);
+    g_return_if_fail (action_cycle != nullptr);
     action_split_horizontal = moo_window_get_action (MOO_WINDOW (window), "SplitViewHorizontal");
-    g_return_if_fail (action_split_horizontal != NULL);
+    g_return_if_fail (action_split_horizontal != nullptr);
     action_split_vertical = moo_window_get_action (MOO_WINDOW (window), "SplitViewVertical");
-    g_return_if_fail (action_split_vertical != NULL);
+    g_return_if_fail (action_split_vertical != nullptr);
 
     has_split_horizontal = _moo_edit_tab_get_split_horizontal (tab);
     has_split_vertical = _moo_edit_tab_get_split_vertical (tab);
diff --git a/moo/mooedit/moolangmgr.cpp b/moo/mooedit/moolangmgr.cpp
index cdb091ef..0f69c83e 100644
--- a/moo/mooedit/moolangmgr.cpp
+++ b/moo/mooedit/moolangmgr.cpp
@@ -75,7 +75,7 @@ moo_lang_mgr_init (MooLangMgr *mgr)
 
     mgr->lang_mgr = gtk_source_language_manager_new ();
     dirs = moo_get_data_subdirs (LANGUAGE_DIR);
-    g_object_set (mgr->lang_mgr, "search-path", dirs, NULL);
+    g_object_set (mgr->lang_mgr, "search-path", dirs, nullptr);
     mgr->style_mgr = gtk_source_style_scheme_manager_new ();
     gtk_source_style_scheme_manager_set_search_path (mgr->style_mgr, dirs);
 
diff --git a/moo/mooedit/mootextbtree.c b/moo/mooedit/mootextbtree.c
index d56f325f..123fbced 100644
--- a/moo/mooedit/mootextbtree.c
+++ b/moo/mooedit/mootextbtree.c
@@ -322,7 +322,7 @@ static void
 merge_nodes (BTNode *parent, guint first)
 {
     BTNode *node, *next;
-    guint i;
+    int i;
 
     g_assert (first + 1 < parent->n_children);
 
diff --git a/moo/mooedit/mootextview.c b/moo/mooedit/mootextview.c
index 532bf715..de7faf33 100644
--- a/moo/mooedit/mootextview.c
+++ b/moo/mooedit/mootextview.c
@@ -3725,6 +3725,7 @@ moo_text_view_size_allocate (GtkWidget     *widget,
         {
             case MOO_TEXT_VIEW_POS_RIGHT:
                 child_alloc.x = MAX (allocation->width - border_width - right, 0);
+                // fallthrough
             case MOO_TEXT_VIEW_POS_LEFT:
                 child_alloc.width = child_req.width;
                 child_alloc.height = MAX (allocation->height - 2*border_width - top - bottom, 1);
@@ -3732,6 +3733,7 @@ moo_text_view_size_allocate (GtkWidget     *widget,
 
             case MOO_TEXT_VIEW_POS_BOTTOM:
                 child_alloc.y = MAX (allocation->height - bottom - border_width, 0);
+                // fallthrough
             case MOO_TEXT_VIEW_POS_TOP:
                 child_alloc.height = child_req.height;
                 child_alloc.width = MAX (allocation->width - 2*border_width - left - right, 1);
diff --git a/moo/moofileview/moofileview.c b/moo/moofileview/moofileview.c
index 92e8d8db..d11281ee 100644
--- a/moo/moofileview/moofileview.c
+++ b/moo/moofileview/moofileview.c
@@ -1384,11 +1384,13 @@ init_gui (MooFileView *fileview)
                                            TREEVIEW_PAGE);
             _moo_tree_view_set_active (fileview->priv->view,
                                        GTK_WIDGET (fileview->priv->treeview));
+            break;
 
         case MOO_FILE_VIEW_BOOKMARK:
             fileview->priv->file_view_type = MOO_FILE_VIEW_ICON;
             gtk_notebook_set_current_page (GTK_NOTEBOOK (notebook),
                                            BOOKMARK_PAGE);
+            break;
     }
 
     moo_file_view_focus_files (fileview);
diff --git a/moo/moolua/lua/luaall.cpp b/moo/moolua/lua/luaall.cpp
index b299c4a5..04ae6622 100644
--- a/moo/moolua/lua/luaall.cpp
+++ b/moo/moolua/lua/luaall.cpp
@@ -2,6 +2,10 @@
 * all.c -- Lua core, libraries and interpreter in a single file
 */
 
+#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#pragma GCC diagnostic ignored "-Wsign-compare"
+#pragma GCC diagnostic ignored "-Wmisleading-indentation"
+
 #define luaall_c
 
 #include "lapi.c"
diff --git a/moo/moopython/moopython-tests.cpp b/moo/moopython/moopython-tests.cpp
index 0e09037d..62959f8f 100644
--- a/moo/moopython/moopython-tests.cpp
+++ b/moo/moopython/moopython-tests.cpp
@@ -22,7 +22,7 @@ test_func (MooTestEnv *env)
     {
         char *dir;
         been_here = TRUE;
-        dir = g_build_filename (moo_test_get_data_dir ().get(), "test-python", NULL);
+        dir = g_build_filename (moo_test_get_data_dir ().get(), "test-python", nullptr);
         moo_python_add_path (dir);
         g_free (dir);
     }
diff --git a/moo/mooutils/moo-test-utils.cpp b/moo/mooutils/moo-test-utils.cpp
index b0b565de..7bdbae43 100644
--- a/moo/mooutils/moo-test-utils.cpp
+++ b/moo/mooutils/moo-test-utils.cpp
@@ -404,7 +404,7 @@ moo_test_find_data_file (const char *basename)
     g_return_val_if_fail(!registry.data_dir.empty(), gstr());
 
     if (!_moo_path_is_absolute(basename))
-        return gstr::take(g_build_filename(registry.data_dir.get(), basename, NULL));
+        return gstr::take(g_build_filename(registry.data_dir.get(), basename, nullptr));
     else
         return gstr(basename);
 }
@@ -421,7 +421,7 @@ moo_test_list_data_files (const char *dir)
     if (!_moo_path_is_absolute (dir))
     {
         g_return_val_if_fail (registry.data_dir != nullptr, NULL);
-        tmp.steal(g_build_filename(registry.data_dir.get(), dir, NULL));
+        tmp.steal(g_build_filename(registry.data_dir.get(), dir, nullptr));
         dir = tmp.get();
     }
 
@@ -454,7 +454,7 @@ moo_test_load_data_file (const char *basename)
     g_return_val_if_fail (registry.data_dir != nullptr, NULL);
 
     if (!_moo_path_is_absolute (basename))
-        fullname = g_build_filename (registry.data_dir.get(), basename, NULL);
+        fullname = g_build_filename (registry.data_dir.get(), basename, nullptr);
     else
         fullname = g_strdup (basename);
 
diff --git a/moo/mooutils/mooapp-ipc.c b/moo/mooutils/mooapp-ipc.c
index a2535906..3379520c 100644
--- a/moo/mooutils/mooapp-ipc.c
+++ b/moo/mooutils/mooapp-ipc.c
@@ -244,7 +244,7 @@ moo_ipc_send (GObject    *sender,
     g_string_append (header, ipc_data.app_id);
     g_string_append_printf (header, "%08x", ++ipc_data.stamp);
 
-    g_string_append_printf (header, "%04x", id_len);
+    g_string_append_printf (header, "%04x", (unsigned) id_len);
     g_string_append (header, id);
 
     _moo_app_input_broadcast (header->str, data, len);
diff --git a/moo/mooutils/mooentry.cpp b/moo/mooutils/mooentry.cpp
index 74a3174e..708f29fb 100644
--- a/moo/mooutils/mooentry.cpp
+++ b/moo/mooutils/mooentry.cpp
@@ -918,7 +918,7 @@ insert_action_merge (InsertAction   *last_action,
         return FALSE;
     }
 
-    tmp = g_strconcat (last_action->text, action->text, NULL);
+    tmp = g_strconcat (last_action->text, action->text, nullptr);
     g_free (last_action->text);
     last_action->length += action->length;
     last_action->text = tmp;
@@ -953,7 +953,7 @@ delete_action_merge (DeleteAction   *last_action,
             return FALSE;
         }
 
-        tmp = g_strconcat (last_action->text, action->text, NULL);
+        tmp = g_strconcat (last_action->text, action->text, nullptr);
         g_free (last_action->text);
         last_action->end += (action->end - action->start);
         last_action->text = tmp;
@@ -967,7 +967,7 @@ delete_action_merge (DeleteAction   *last_action,
             return FALSE;
         }
 
-        tmp = g_strconcat (action->text, last_action->text, NULL);
+        tmp = g_strconcat (action->text, last_action->text, nullptr);
         g_free (last_action->text);
         last_action->start = action->start;
         last_action->text = tmp;
diff --git a/moo/mooutils/moofilewriter.cpp b/moo/mooutils/moofilewriter.cpp
index 16c7f138..35a6733e 100644
--- a/moo/mooutils/moofilewriter.cpp
+++ b/moo/mooutils/moofilewriter.cpp
@@ -631,8 +631,8 @@ test_moo_file_writer (void)
     GError *error = NULL;
 
     dir = moo_test_get_working_dir ();
-    my_dir = g_build_filename (dir, "cfg-writer", NULL);
-    filename = g_build_filename (my_dir, "configfile", NULL);
+    my_dir = g_build_filename (dir, "cfg-writer", nullptr);
+    filename = g_build_filename (my_dir, "configfile", nullptr);
     bak_filename = g_strdup_printf ("%s~", filename);
 
     writer = moo_config_writer_new (filename, TRUE, &error);
diff --git a/moo/mooutils/mooi18n.cpp b/moo/mooutils/mooi18n.cpp
index fcf50e62..1a678886 100644
--- a/moo/mooutils/mooi18n.cpp
+++ b/moo/mooutils/mooi18n.cpp
@@ -92,7 +92,7 @@ moo_pgettext2 (G_GNUC_UNUSED const char *context, const char *msgctxtid)
     g_return_val_if_fail (msgctxtid != NULL, NULL);
     init_gettext ();
 
-    tmp = g_strjoin (context, "\004", msgctxtid, NULL);
+    tmp = g_strjoin (context, "\004", msgctxtid, nullptr);
     translation = dgettext (GETTEXT_PACKAGE, tmp);
 
     if (translation == tmp)
@@ -171,8 +171,8 @@ test_mooi18n (void)
     char *po_file, *po_file2;
 
     locale_dir = moo_get_locale_dir ();
-    po_file = g_build_filename (locale_dir, "ru", "LC_MESSAGES", GETTEXT_PACKAGE ".mo", NULL);
-    po_file2 = g_build_filename (locale_dir, "ru", "LC_MESSAGES", GETTEXT_PACKAGE "-gsv.mo", NULL);
+    po_file = g_build_filename (locale_dir, "ru", "LC_MESSAGES", GETTEXT_PACKAGE ".mo", nullptr);
+    po_file2 = g_build_filename (locale_dir, "ru", "LC_MESSAGES", GETTEXT_PACKAGE "-gsv.mo", nullptr);
 
     TEST_ASSERT_MSG (g_file_test (po_file, G_FILE_TEST_EXISTS), "mo file '%s' does not exist", po_file);
     TEST_ASSERT_MSG (g_file_test (po_file2, G_FILE_TEST_EXISTS), "mo file '%s' does not exist", po_file2);
diff --git a/moo/mooutils/moopaned.c b/moo/mooutils/moopaned.c
index db17fe74..be092027 100644
--- a/moo/mooutils/moopaned.c
+++ b/moo/mooutils/moopaned.c
@@ -1659,6 +1659,7 @@ draw_border (MooPaned       *paned,
             rect.x = widget->allocation.width -
                         paned->priv->button_box_size -
                         paned->priv->border_size;
+            // fallthrough
         case MOO_PANE_POS_LEFT:
             rect.y = 0;
             rect.height = widget->allocation.height;
@@ -1679,6 +1680,7 @@ draw_border (MooPaned       *paned,
             rect.y = widget->allocation.height -
                     paned->priv->button_box_size -
                     paned->priv->border_size;
+            // fallthrough
         case MOO_PANE_POS_TOP:
             rect.x = 0;
             rect.width = widget->allocation.width;
@@ -2043,12 +2045,14 @@ _moo_paned_get_button_position (MooPaned     *paned,
         {
             case MOO_PANE_POS_RIGHT:
                 rect->x = widget->allocation.width - 30;
+                // fallthrough
             case MOO_PANE_POS_LEFT:
                 rect->height = 60;
                 rect->width = 30;
                 break;
             case MOO_PANE_POS_BOTTOM:
                 rect->y = widget->allocation.height - 30;
+                // fallthrough
             case MOO_PANE_POS_TOP:
                 rect->width = 60;
                 rect->height = 30;
diff --git a/moo/mooutils/mooutils-fs.cpp b/moo/mooutils/mooutils-fs.cpp
index 95b995d1..e2bb7a29 100644
--- a/moo/mooutils/mooutils-fs.cpp
+++ b/moo/mooutils/mooutils-fs.cpp
@@ -526,7 +526,7 @@ _moo_filename_to_uri (const char *file,
     if (!_moo_path_is_absolute (file))
     {
         char *cd = g_get_current_dir ();
-        file = freeme = g_build_filename (cd, file, NULL);
+        file = freeme = g_build_filename (cd, file, nullptr);
         g_free (cd);
     }
 
@@ -731,7 +731,7 @@ normalize_full_path_win32 (const char *fullpath)
     {
         if (prefix)
         {
-            char *tmp = g_strconcat (prefix, path, NULL);
+            char *tmp = g_strconcat (prefix, path, nullptr);
             g_free (path);
             path = tmp;
         }
@@ -764,7 +764,7 @@ normalize_path (const char *filename)
     {
         char *working_dir = g_get_current_dir ();
         g_return_val_if_fail (working_dir != NULL, g_strdup (filename));
-        freeme = g_build_filename (working_dir, filename, NULL);
+        freeme = g_build_filename (working_dir, filename, nullptr);
         filename = freeme;
         g_free (working_dir);
     }
@@ -925,7 +925,7 @@ make_cases (gboolean unix_paths)
         {
             g_ptr_array_add (paths, g_strdup (rel_files_common[i]));
             if (rel_files_common[i+1])
-                g_ptr_array_add (paths, g_build_filename (current_dir, rel_files_common[i+1], NULL));
+                g_ptr_array_add (paths, g_build_filename (current_dir, rel_files_common[i+1], nullptr));
             else
                 g_ptr_array_add (paths, g_strdup (current_dir));
         }
@@ -936,7 +936,7 @@ make_cases (gboolean unix_paths)
         {
             g_ptr_array_add (paths, g_strdup (rel_files_unix[i]));
             if (rel_files_unix[i+1])
-                g_ptr_array_add (paths, g_build_filename (current_dir, rel_files_unix[i+1], NULL));
+                g_ptr_array_add (paths, g_build_filename (current_dir, rel_files_unix[i+1], nullptr));
             else
                 g_ptr_array_add (paths, g_strdup (current_dir));
         }
diff --git a/moo/mooutils/mooutils-misc.cpp b/moo/mooutils/mooutils-misc.cpp
index c9fc6544..b241fe10 100644
--- a/moo/mooutils/mooutils-misc.cpp
+++ b/moo/mooutils/mooutils-misc.cpp
@@ -686,7 +686,7 @@ moo_log_window_insert (MooLogWindow *log,
 {
     GtkTextIter iter;
     gtk_text_buffer_get_end_iter (log->buf, &iter);
-    gtk_text_buffer_insert_with_tags (log->buf, &iter, text, -1, tag, NULL);
+    gtk_text_buffer_insert_with_tags (log->buf, &iter, text, -1, tag, nullptr);
     gtk_text_view_scroll_mark_onscreen (log->textview, log->insert);
 }
 
@@ -1193,7 +1193,7 @@ moo_get_user_cache_dir (void)
     G_LOCK (moo_user_cache_dir);
 
     if (!moo_user_cache_dir)
-        moo_user_cache_dir = g_build_filename (g_get_user_cache_dir (), MOO_PACKAGE_NAME, NULL);
+        moo_user_cache_dir = g_build_filename (g_get_user_cache_dir (), MOO_PACKAGE_NAME, nullptr);
 
     G_UNLOCK (moo_user_cache_dir);
 
@@ -1277,7 +1277,7 @@ moo_get_user_data_dir (void)
 
         moo_user_data_dir = g_build_filename (basedir,
                                               MOO_PACKAGE_NAME,
-                                              NULL);
+                                              nullptr);
 
         g_free (freeme);
     }
@@ -1340,7 +1340,7 @@ moo_make_user_data_dir (const char *path)
     user_dir = moo_get_user_data_dir ();
     g_return_val_if_fail (user_dir != NULL, FALSE);
 
-    full_path = g_build_filename (user_dir, path, NULL);
+    full_path = g_build_filename (user_dir, path, nullptr);
     result = _moo_mkdir_with_parents (full_path, &err);
 
     if (result != 0)
@@ -1428,7 +1428,7 @@ enumerate_data_dirs (MooDataDirType  type,
             const char* const *p;
 
             for (p = g_get_system_data_dirs (); p && *p; ++p)
-                g_ptr_array_add (dirs, g_build_filename (*p, MOO_PACKAGE_NAME, NULL));
+                g_ptr_array_add (dirs, g_build_filename (*p, MOO_PACKAGE_NAME, nullptr));
 
             g_ptr_array_add (dirs, g_strdup (MOO_DATA_DIR));
         }
@@ -1576,7 +1576,7 @@ moo_get_stuff_subdirs (const char    *subdir,
     dirs = g_new0 (char*, n_dirs + 1);
 
     for (i = 0; i < n_dirs; ++i)
-        dirs[i] = g_build_filename (data_dirs[i], subdir, NULL);
+        dirs[i] = g_build_filename (data_dirs[i], subdir, nullptr);
 
     g_strfreev (data_dirs);
     return dirs;
@@ -1650,7 +1650,7 @@ get_user_data_file (const char *basename,
 
     g_return_val_if_fail (dir != NULL, NULL);
 
-    file = g_build_filename (dir, basename, NULL);
+    file = g_build_filename (dir, basename, nullptr);
 
     g_free (dir);
     return file;
diff --git a/moo/plugins/moofilelist.cpp b/moo/plugins/moofilelist.cpp
index 459a46a0..ef3f3c6d 100644
--- a/moo/plugins/moofilelist.cpp
+++ b/moo/plugins/moofilelist.cpp
@@ -195,7 +195,7 @@ file_list_init (FileList *list)
     gtk_tree_store_set_column_types (GTK_TREE_STORE (list), 2, types);
 
     list->n_user_items = 0;
-    list->docs = NULL;
+    list->docs = nullptr;
 }
 
 static void
@@ -217,7 +217,7 @@ static Item *
 get_item_at_iter (FileList    *list,
                   GtkTreeIter *iter)
 {
-    Item *item = NULL;
+    Item *item = nullptr;
 
     gtk_tree_model_get (GTK_TREE_MODEL (list), iter, COLUMN_ITEM, &item, -1);
 
@@ -234,7 +234,7 @@ get_item_at_path (FileList    *list,
     GtkTreeIter iter;
 
     if (!gtk_tree_model_get_iter (GTK_TREE_MODEL (list), &iter, path))
-        return NULL;
+        return nullptr;
     else
         return get_item_at_iter (list, &iter);
 }
@@ -315,10 +315,10 @@ file_new (void)
     ITEM (file)->ref_count = 1;
     ITEM (file)->type = ITEM_FILE;
 
-    file->uri = NULL;
-    file->doc = NULL;
-    file->display_name = NULL;
-    file->display_basename = NULL;
+    file->uri = nullptr;
+    file->doc = nullptr;
+    file->display_name = nullptr;
+    file->display_basename = nullptr;
 
     return file;
 }
@@ -328,7 +328,7 @@ file_new_doc (MooEdit *doc)
 {
     File *file;
 
-    g_return_val_if_fail (MOO_IS_EDIT (doc), NULL);
+    g_return_val_if_fail (MOO_IS_EDIT (doc), nullptr);
 
     file = file_new ();
     file_set_doc (file, doc);
@@ -343,8 +343,8 @@ file_set_uri (File       *file,
     char *tmp;
     char *filename;
 
-    g_return_if_fail (file != NULL);
-    g_return_if_fail (uri != NULL);
+    g_return_if_fail (file != nullptr);
+    g_return_if_fail (uri != nullptr);
 
     tmp = file->uri;
     file->uri = g_strdup (uri);
@@ -353,7 +353,7 @@ file_set_uri (File       *file,
     g_free (file->display_name);
     g_free (file->display_basename);
 
-    filename = g_filename_from_uri (uri, NULL, NULL);
+    filename = g_filename_from_uri (uri, nullptr, nullptr);
 
     if (filename)
     {
@@ -374,7 +374,7 @@ file_new_uri (const char *uri)
 {
     File *file;
 
-    g_return_val_if_fail (uri != NULL, NULL);
+    g_return_val_if_fail (uri != nullptr, nullptr);
 
     file = file_new ();
     file_set_uri (file, uri);
@@ -402,7 +402,7 @@ item_get_tooltip (Item *item)
     if (ITEM_IS_FILE (item))
         return FILE_ITEM (item)->display_name;
     else
-        return NULL;
+        return nullptr;
 }
 
 static Item *
@@ -455,7 +455,7 @@ check_list (G_GNUC_UNUSED FileList *list)
     GtkTreeIter iter;
     int index = 0;
 
-    if (gtk_tree_model_iter_children (GTK_TREE_MODEL (list), &iter, NULL))
+    if (gtk_tree_model_iter_children (GTK_TREE_MODEL (list), &iter, nullptr))
     {
         do
         {
@@ -463,12 +463,12 @@ check_list (G_GNUC_UNUSED FileList *list)
 
             if (list->n_user_items)
             {
-                g_assert (index == list->n_user_items || item != NULL);
-                g_assert (index != list->n_user_items || item == NULL);
+                g_assert (index == list->n_user_items || item != nullptr);
+                g_assert (index != list->n_user_items || item == nullptr);
             }
             else
             {
-                g_assert (item != NULL);
+                g_assert (item != nullptr);
             }
 
             index += 1;
@@ -477,7 +477,7 @@ check_list (G_GNUC_UNUSED FileList *list)
     }
 
     g_assert (list->n_user_items == 0 ||
-              list->n_user_items < gtk_tree_model_iter_n_children (GTK_TREE_MODEL (list), NULL));
+              list->n_user_items < gtk_tree_model_iter_n_children (GTK_TREE_MODEL (list), nullptr));
 #endif
 }
 
@@ -519,7 +519,7 @@ file_list_find_uri (FileList    *list,
                     const char  *uri,
                     GtkTreeIter *iter)
 {
-    return iter_find_uri (list, uri, NULL, iter);
+    return iter_find_uri (list, uri, nullptr, iter);
 }
 
 
@@ -543,7 +543,7 @@ file_list_remove_row (FileList    *list,
     if (last_user_item)
     {
         GtkTreeIter sep;
-        gtk_tree_model_iter_nth_child (GTK_TREE_MODEL (list), &sep, NULL, 0);
+        gtk_tree_model_iter_nth_child (GTK_TREE_MODEL (list), &sep, nullptr, 0);
         gtk_tree_store_remove (GTK_TREE_STORE (list), &sep);
     }
 
@@ -555,7 +555,7 @@ file_list_append_row (FileList    *list,
                       Item        *item,
                       GtkTreeIter *iter)
 {
-    gtk_tree_store_append (GTK_TREE_STORE (list), iter, NULL);
+    gtk_tree_store_append (GTK_TREE_STORE (list), iter, nullptr);
     gtk_tree_store_set (GTK_TREE_STORE (list), iter,
                         COLUMN_ITEM, item,
                         COLUMN_TOOLTIP, item_get_tooltip (item),
@@ -596,7 +596,7 @@ file_list_insert_row (FileList    *list,
     if (first_user_item)
     {
         GtkTreeIter sep;
-        gtk_tree_store_insert (GTK_TREE_STORE (list), &sep, NULL, list->n_user_items);
+        gtk_tree_store_insert (GTK_TREE_STORE (list), &sep, nullptr, list->n_user_items);
         gtk_tree_model_iter_nth_child (GTK_TREE_MODEL (list), iter, parent_iter, index);
     }
 
@@ -639,7 +639,7 @@ get_doc_row (FileList *list, MooEdit *doc)
 {
     GtkTreeRowReference *row = file_list_row_data.get(doc);
     if (row && g_object_get_qdata (G_OBJECT (doc), FILE_LIST_QUARK) != list->plugin)
-        row = NULL;
+        row = nullptr;
     return row;
 }
 
@@ -724,14 +724,14 @@ file_list_update_doc (FileList *list,
 
     item = get_item_at_iter (list, &iter);
     DEBUG_ASSERT (ITEM_IS_FILE (item) && FILE_ITEM (item)->doc == doc);
-    DEBUG_ASSERT (FILE_ITEM (item)->uri != NULL);
+    DEBUG_ASSERT (FILE_ITEM (item)->uri != nullptr);
 
     gstr new_uri = gstr::take (moo_edit_get_uri (doc));
 
     if (new_uri.empty() || strcmp (new_uri.get(), FILE_ITEM (item)->uri) != 0)
     {
         file_list_row_data.set(doc, nullptr);
-        file_set_doc (FILE_ITEM (item), NULL);
+        file_set_doc (FILE_ITEM (item), nullptr);
         file_list_add_doc (list, doc, FALSE);
     }
 }
@@ -742,7 +742,7 @@ file_list_remove_doc (FileList *list,
 {
     GtkTreeIter iter;
 
-    DEBUG_ASSERT (g_slist_find (list->docs, doc) != NULL);
+    DEBUG_ASSERT (g_slist_find (list->docs, doc) != nullptr);
 
     if (doc_get_list_iter (list, doc, &iter))
     {
@@ -755,13 +755,13 @@ file_list_remove_doc (FileList *list,
         if (file_list_iter_is_auto (list, &iter))
             file_list_remove_row (list, &iter);
         else
-            file_set_doc (FILE_ITEM (item), NULL);
+            file_set_doc (FILE_ITEM (item), nullptr);
     }
 
     if (get_doc_row (list, doc))
     {
         file_list_row_data.set(doc, nullptr);
-        g_object_set_qdata (G_OBJECT (doc), FILE_LIST_QUARK, NULL);
+        g_object_set_qdata (G_OBJECT (doc), FILE_LIST_QUARK, nullptr);
     }
 
     disconnect_doc (list, doc);
@@ -774,10 +774,10 @@ remove_auto_items (FileList *list)
 
     if (list->n_user_items)
         while (gtk_tree_model_iter_nth_child (GTK_TREE_MODEL (list), &iter,
-                                              NULL, list->n_user_items + 1))
+                                              nullptr, list->n_user_items + 1))
             gtk_tree_store_remove (GTK_TREE_STORE (list), &iter);
     else
-        while (gtk_tree_model_iter_nth_child (GTK_TREE_MODEL (list), &iter, NULL, 0))
+        while (gtk_tree_model_iter_nth_child (GTK_TREE_MODEL (list), &iter, nullptr, 0))
             gtk_tree_store_remove (GTK_TREE_STORE (list), &iter);
 }
 
@@ -790,13 +790,13 @@ file_list_update (FileList *list,
 
     remove_auto_items (list);
 
-    for (l = docs; l != NULL; l = l->next)
+    for (l = docs; l != nullptr; l = l->next)
         file_list_update_doc (list, (MooEdit*) l->data);
 
     old_docs = g_slist_copy (list->docs);
-    for (l = docs; l != NULL; l = l->next)
+    for (l = docs; l != nullptr; l = l->next)
         old_docs = g_slist_remove (old_docs, l->data);
-    for (l = old_docs; l != NULL; l = l->next)
+    for (l = old_docs; l != nullptr; l = l->next)
         file_list_remove_doc (list, (MooEdit*) l->data);
 
     check_list (list);
@@ -818,13 +818,13 @@ file_list_shutdown (FileList *list)
         {
             Item *item = get_item_at_iter (list, &iter);
             DEBUG_ASSERT (ITEM_IS_FILE (item));
-            file_set_doc (FILE_ITEM (item), NULL);
+            file_set_doc (FILE_ITEM (item), nullptr);
         }
 
         if (get_doc_row (list, doc))
         {
             file_list_row_data.set(doc, nullptr);
-            g_object_set_qdata (G_OBJECT (doc), FILE_LIST_QUARK, NULL);
+            g_object_set_qdata (G_OBJECT (doc), FILE_LIST_QUARK, nullptr);
         }
 
         disconnect_doc (list, doc);
@@ -836,8 +836,8 @@ static UIConfig *
 ui_config_new (void)
 {
     UIConfig *cfg = g_new0 (UIConfig, 1);
-    cfg->expanded_rows = NULL;
-    cfg->selected_row = NULL;
+    cfg->expanded_rows = nullptr;
+    cfg->selected_row = nullptr;
     return cfg;
 }
 
@@ -846,7 +846,7 @@ ui_config_free (UIConfig *cfg)
 {
     if (cfg)
     {
-        g_slist_foreach (cfg->expanded_rows, (GFunc) gtk_tree_path_free, NULL);
+        g_slist_foreach (cfg->expanded_rows, (GFunc) gtk_tree_path_free, nullptr);
         g_slist_free (cfg->expanded_rows);
         gtk_tree_path_free (cfg->selected_row);
         g_free (cfg);
@@ -879,7 +879,7 @@ parse_node (FileList      *list,
         file_list_insert_row (list, ITEM (group), &iter, parent, -1);
         item_unref (ITEM (group));
 
-        for (child = elm->children; child != NULL; child = child->next)
+        for (child = elm->children; child != nullptr; child = child->next)
             if (MOO_MARKUP_IS_ELEMENT (child))
                 parse_node (list, child, &iter, filename, ui_config);
     }
@@ -905,7 +905,7 @@ parse_node (FileList      *list,
         const char *expanded_rows;
         const char *selected_row;
         UIConfig *config;
-        char **rows = NULL, **p;
+        char **rows = nullptr, **p;
 
         if (*ui_config)
         {
@@ -949,11 +949,11 @@ file_list_load_config (FileList    *list,
                        UIConfig   **ui_configp)
 {
     MooMarkupDoc *doc;
-    GError *error = NULL;
+    GError *error = nullptr;
     MooMarkupNode *root, *node;
     const char *version;
 
-    *ui_configp = NULL;
+    *ui_configp = nullptr;
 
     if (!g_file_test (filename, G_FILE_TEST_EXISTS))
         return;
@@ -984,12 +984,12 @@ file_list_load_config (FileList    *list,
         goto out;
     }
 
-    for (node = root->children; node != NULL; node = node->next)
+    for (node = root->children; node != nullptr; node = node->next)
     {
         if (!MOO_MARKUP_IS_ELEMENT (node))
             continue;
 
-        parse_node (list, node, NULL, filename, ui_configp);
+        parse_node (list, node, nullptr, filename, ui_configp);
     }
 
 out:
@@ -1061,7 +1061,7 @@ file_list_save_config (FileList   *list,
 {
     GtkTreeIter iter;
     GString *buffer;
-    GError *error = NULL;
+    GError *error = nullptr;
 
     if (!gtk_tree_model_get_iter_first (GTK_TREE_MODEL (list), &iter))
     {
@@ -1083,7 +1083,7 @@ file_list_save_config (FileList   *list,
 
             g_string_append (buffer, " " PROP_EXPANDED_ROWS "=\"");
 
-            for (l = ui_config->expanded_rows; l != NULL; l = l->next)
+            for (l = ui_config->expanded_rows; l != nullptr; l = l->next)
             {
                 GtkTreePath *path = (GtkTreePath*) l->data;
                 char *tmp = gtk_tree_path_to_string (path);
@@ -1135,9 +1135,9 @@ static GtkTreePath *
 file_list_add_group (FileList    *list,
                      GtkTreePath *path)
 {
-    GtkTreePath *parent = NULL;
+    GtkTreePath *parent = nullptr;
     GtkTreeIter parent_iter, new_iter;
-    GtkTreeIter *piter = NULL;
+    GtkTreeIter *piter = nullptr;
     Group *group;
     int index = -1;
 
@@ -1205,7 +1205,7 @@ static void
 file_list_remove_items (FileList *list,
                         GList    *paths)
 {
-    GSList *rows = NULL;
+    GSList *rows = nullptr;
 
     while (paths)
     {
@@ -1223,7 +1223,7 @@ file_list_remove_items (FileList *list,
 
     while (rows)
     {
-        GtkTreePath *path = NULL;
+        GtkTreePath *path = nullptr;
 
         if (gtk_tree_row_reference_valid ((GtkTreeRowReference*) rows->data))
             path = gtk_tree_row_reference_get_path ((GtkTreeRowReference*) rows->data);
@@ -1316,12 +1316,12 @@ copy_row (FileList    *list,
 {
     GtkTreeRowReference *source_row;
     GtkTreeIter iter, parent_iter;
-    GtkTreeIter *piter = NULL;
+    GtkTreeIter *piter = nullptr;
     Item *item;
 
     gtk_tree_model_get_iter (GTK_TREE_MODEL (list), &iter, source);
     item = get_item_at_iter (list, &iter);
-    g_return_if_fail (item != NULL);
+    g_return_if_fail (item != nullptr);
 
     source_row = gtk_tree_row_reference_new (GTK_TREE_MODEL (list), source);
 
@@ -1346,7 +1346,7 @@ move_row (FileList    *list,
           GtkTreePath *parent,
           int          index)
 {
-    GtkTreePath *source_parent = NULL;
+    GtkTreePath *source_parent = nullptr;
     gboolean same_parent = FALSE;
     GtkTreeIter iter;
     Item *item;
@@ -1366,7 +1366,7 @@ move_row (FileList    *list,
             file_set_uri (FILE_ITEM (item), uri.get());
 
         file_list_row_data.set(FILE_ITEM (item)->doc, nullptr);
-        file_set_doc (FILE_ITEM (item), NULL);
+        file_set_doc (FILE_ITEM (item), nullptr);
     }
 
     if (gtk_tree_path_get_depth (source) > 1)
@@ -1382,7 +1382,7 @@ move_row (FileList    *list,
 
     if (same_parent)
     {
-        GtkTreeIter *piter = NULL;
+        GtkTreeIter *piter = nullptr;
         gboolean first_user = FALSE;
 
         if (parent)
@@ -1399,7 +1399,7 @@ move_row (FileList    *list,
         if (index >= gtk_tree_model_iter_n_children (GTK_TREE_MODEL (list), piter) || index < 0)
         {
             gtk_tree_model_get_iter (GTK_TREE_MODEL (list), &iter, source);
-            gtk_tree_store_move_before (GTK_TREE_STORE (list), &iter, NULL);
+            gtk_tree_store_move_before (GTK_TREE_STORE (list), &iter, nullptr);
         }
         else
         {
@@ -1411,7 +1411,7 @@ move_row (FileList    *list,
 
         if (first_user)
             gtk_tree_store_insert (GTK_TREE_STORE (list), &iter,
-                                   NULL, list->n_user_items);
+                                   nullptr, list->n_user_items);
     }
     else
     {
@@ -1444,7 +1444,7 @@ uri_is_directory (const char *uri)
     char *filename;
     gboolean retval = FALSE;
 
-    filename = g_filename_from_uri (uri, NULL, NULL);
+    filename = g_filename_from_uri (uri, nullptr, nullptr);
 
     if (filename)
         retval = g_file_test (filename, G_FILE_TEST_IS_DIR);
@@ -1496,9 +1496,9 @@ add_row_from_uri (FileList    *list,
                   int          index)
 {
     GtkTreeIter iter, dummy;
-    GtkTreeIter *piter = NULL;
+    GtkTreeIter *piter = nullptr;
 
-    g_return_val_if_fail (uri != NULL, FALSE);
+    g_return_val_if_fail (uri != nullptr, FALSE);
 
     if (parent)
     {
@@ -1521,10 +1521,10 @@ find_drop_destination (FileList     *list,
                        int          *index)
 {
     int n_children;
-    Group *parent_group = NULL;
+    Group *parent_group = nullptr;
     GtkTreeIter parent_iter;
 
-    *parent_path = NULL;
+    *parent_path = nullptr;
     *index = 0;
 
     if (gtk_tree_path_get_depth (dest) > 1)
@@ -1571,7 +1571,7 @@ find_drop_destination (FileList     *list,
         }
         else
         {
-            parent_group = NULL;
+            parent_group = nullptr;
             *index = gtk_tree_path_get_indices (parent)[0];
         }
 
@@ -1610,7 +1610,7 @@ drop_uris (FileList     *list,
            GtkTreePath  *dest,
            char        **uris)
 {
-    GtkTreePath *parent_path = NULL;
+    GtkTreePath *parent_path = nullptr;
     int index = 0;
 
     if (!find_drop_destination (list, dest, &parent_path, &index))
@@ -1638,7 +1638,7 @@ drop_tree_model_row (FileList    *list,
                      GtkTreePath *dest,
                      GtkTreePath *source)
 {
-    GtkTreePath *parent_path = NULL;
+    GtkTreePath *parent_path = nullptr;
     int index;
     gboolean retval;
 
@@ -1678,10 +1678,10 @@ drag_dest_drag_data_received (GtkTreeDragDest  *drag_dest,
 {
     if (selection_data->target == TREE_MODEL_ROW_ATOM)
     {
-        GtkTreePath *path = NULL;
+        GtkTreePath *path = nullptr;
         gboolean retval;
 
-        if (!gtk_tree_get_row_drag_data (selection_data, NULL, &path))
+        if (!gtk_tree_get_row_drag_data (selection_data, nullptr, &path))
             return FALSE;
 
         if ((retval = drop_tree_model_row (FILE_LIST (drag_dest), dest, path)))
@@ -1729,8 +1729,8 @@ _moo_str_semicase_compare (const char *string,
     gboolean has_upper;
     const char *p;
 
-    g_return_val_if_fail (string != NULL, FALSE);
-    g_return_val_if_fail (key != NULL, FALSE);
+    g_return_val_if_fail (string != nullptr, FALSE);
+    g_return_val_if_fail (key != nullptr, FALSE);
 
     for (p = key, has_upper = FALSE; *p && !has_upper; ++p)
         has_upper = g_ascii_isupper (*p);
@@ -1747,7 +1747,7 @@ row_separator_func (GtkTreeModel *model,
                     GtkTreeIter  *iter)
 {
     Item *item = get_item_at_iter (FILE_LIST (model), iter);
-    return item == NULL;
+    return item == nullptr;
 }
 
 static gboolean
@@ -1756,7 +1756,7 @@ tree_view_search_equal_func (GtkTreeModel *model,
                              const char   *key,
                              GtkTreeIter  *iter)
 {
-    const char *compare_with = NULL;
+    const char *compare_with = nullptr;
     Item *item;
 
     item = get_item_at_iter (FILE_LIST (model), iter);
@@ -1780,9 +1780,9 @@ pixbuf_data_func (G_GNUC_UNUSED GtkTreeViewColumn *column,
 {
     Item *item = get_item_at_iter (FILE_LIST (model), iter);
     if (ITEM_IS_GROUP (item))
-        g_object_set (cell, "stock-id", GTK_STOCK_DIRECTORY, NULL);
+        g_object_set (cell, "stock-id", GTK_STOCK_DIRECTORY, nullptr);
     else if (ITEM_IS_FILE (item))
-        g_object_set (cell, "stock-id", GTK_STOCK_FILE, NULL);
+        g_object_set (cell, "stock-id", GTK_STOCK_FILE, nullptr);
 }
 
 static void
@@ -1794,9 +1794,9 @@ text_data_func (G_GNUC_UNUSED GtkTreeViewColumn *column,
     Item *item = get_item_at_iter (FILE_LIST (model), iter);
 
     if (ITEM_IS_GROUP (item))
-        g_object_set (cell, "text", GROUP_ITEM (item)->name, NULL);
+        g_object_set (cell, "text", GROUP_ITEM (item)->name, nullptr);
     else if (ITEM_IS_FILE (item))
-        g_object_set (cell, "text", FILE_ITEM (item)->display_basename, NULL);
+        g_object_set (cell, "text", FILE_ITEM (item)->display_basename, nullptr);
 }
 
 static void
@@ -1809,10 +1809,10 @@ text_cell_edited (GtkCellRenderer *cell,
     Item *item;
     GtkTreePath *path;
 
-    g_object_set (cell, "editable", FALSE, NULL);
+    g_object_set (cell, "editable", FALSE, nullptr);
 
     path = gtk_tree_path_new_from_string (path_string);
-    g_return_if_fail (path != NULL);
+    g_return_if_fail (path != nullptr);
 
     gtk_tree_model_get_iter (GTK_TREE_MODEL (plugin->list), &iter, path);
     item = get_item_at_iter (plugin->list, &iter);
@@ -1827,14 +1827,14 @@ text_cell_edited (GtkCellRenderer *cell,
 static void
 text_cell_editing_canceled (GtkCellRenderer *cell)
 {
-    g_object_set (cell, "editable", FALSE, NULL);
+    g_object_set (cell, "editable", FALSE, nullptr);
 }
 
 static void
 start_edit (WindowPlugin *plugin,
             GtkTreePath  *path)
 {
-    g_object_set (plugin->text_cell, "editable", TRUE, NULL);
+    g_object_set (plugin->text_cell, "editable", TRUE, nullptr);
     gtk_tree_view_set_cursor_on_cell (plugin->treeview,
                                       path, plugin->column,
                                       plugin->text_cell,
@@ -1846,13 +1846,13 @@ get_selected_rows (WindowPlugin *plugin)
 {
     GtkTreeSelection *selection;
     selection = gtk_tree_view_get_selection (plugin->treeview);
-    return gtk_tree_selection_get_selected_rows (selection, NULL);
+    return gtk_tree_selection_get_selected_rows (selection, nullptr);
 }
 
 static void
 path_list_free (GList *paths)
 {
-    g_list_foreach (paths, (GFunc) gtk_tree_path_free, NULL);
+    g_list_foreach (paths, (GFunc) gtk_tree_path_free, nullptr);
     g_list_free (paths);
 }
 
@@ -1893,7 +1893,7 @@ add_group_activated (G_GNUC_UNUSED GtkWidget *menuitem,
     if (selected)
         path = (GtkTreePath*) g_list_last (selected)->data;
     else
-        path = NULL;
+        path = nullptr;
 
     new_path = file_list_add_group (plugin->list, path);
 
@@ -1937,7 +1937,7 @@ open_file (WindowPlugin *plugin,
     Item *item;
 
     item = get_item_at_path (plugin->list, path);
-    g_return_if_fail (item != NULL);
+    g_return_if_fail (item != nullptr);
 
     if (ITEM_IS_FILE (item))
     {
@@ -1950,7 +1950,7 @@ open_file (WindowPlugin *plugin,
         else
         {
             moo_editor_open_uri (moo_editor_instance (),
-                                 FILE_ITEM (item)->uri, NULL, -1,
+                                 FILE_ITEM (item)->uri, nullptr, -1,
                                  MOO_WIN_PLUGIN (plugin)->window);
         }
     }
@@ -1986,7 +1986,7 @@ open_activated (G_GNUC_UNUSED GtkWidget *menuitem,
 
     selected = get_selected_rows (plugin);
 
-    for (l = selected; l != NULL; l = l->next)
+    for (l = selected; l != nullptr; l = l->next)
         open_file (plugin, (GtkTreePath*) l->data);
 
     path_list_free (selected);
@@ -1997,7 +1997,7 @@ can_open (G_GNUC_UNUSED FileList *list,
           GList *paths)
 {
     /* XXX */
-    return paths != NULL;
+    return paths != nullptr;
 }
 
 static gboolean
@@ -2027,26 +2027,26 @@ popup_menu (WindowPlugin *plugin,
     GtkTreePath *single_path;
     Item *single_item;
 
-    single_path = (selected && !selected->next) ? (GtkTreePath*) selected->data : NULL;
-    single_item = single_path ? get_item_at_path (plugin->list, single_path) : NULL;
+    single_path = (selected && !selected->next) ? (GtkTreePath*) selected->data : nullptr;
+    single_item = single_path ? get_item_at_path (plugin->list, single_path) : nullptr;
 
     menu = gtk_menu_new ();
 
     if (can_open (plugin->list, selected))
     {
-        menuitem = gtk_image_menu_item_new_from_stock (GTK_STOCK_OPEN, NULL);
+        menuitem = gtk_image_menu_item_new_from_stock (GTK_STOCK_OPEN, nullptr);
         g_signal_connect (menuitem, "activate", G_CALLBACK (open_activated), plugin);
         gtk_menu_shell_append (GTK_MENU_SHELL (menu), menuitem);
     }
 
-    menuitem = gtk_image_menu_item_new_from_stock (GTK_STOCK_ADD, NULL);
+    menuitem = gtk_image_menu_item_new_from_stock (GTK_STOCK_ADD, nullptr);
     gtk_label_set_text (GTK_LABEL (GTK_BIN (menuitem)->child), "Add Group");
     g_signal_connect (menuitem, "activate", G_CALLBACK (add_group_activated), plugin);
     gtk_menu_shell_append (GTK_MENU_SHELL (menu), menuitem);
 
     if (selected)
     {
-        menuitem = gtk_image_menu_item_new_from_stock (GTK_STOCK_REMOVE, NULL);
+        menuitem = gtk_image_menu_item_new_from_stock (GTK_STOCK_REMOVE, nullptr);
         g_signal_connect (menuitem, "activate", G_CALLBACK (remove_activated), plugin);
         gtk_widget_set_sensitive (menuitem, can_remove (plugin->list, selected));
         gtk_menu_shell_append (GTK_MENU_SHELL (menu), menuitem);
@@ -2054,14 +2054,14 @@ popup_menu (WindowPlugin *plugin,
 
     if (single_item && ITEM_IS_GROUP (single_item))
     {
-        menuitem = gtk_image_menu_item_new_from_stock (GTK_STOCK_EDIT, NULL);
+        menuitem = gtk_image_menu_item_new_from_stock (GTK_STOCK_EDIT, nullptr);
         gtk_label_set_text (GTK_LABEL (GTK_BIN (menuitem)->child), "Rename");
         g_signal_connect (menuitem, "activate", G_CALLBACK (rename_activated), plugin);
         gtk_menu_shell_append (GTK_MENU_SHELL (menu), menuitem);
     }
 
     gtk_widget_show_all (menu);
-    gtk_menu_popup (GTK_MENU (menu), NULL, NULL, NULL, NULL, button, time);
+    gtk_menu_popup (GTK_MENU (menu), nullptr, nullptr, nullptr, nullptr, button, time);
 }
 
 static gboolean
@@ -2070,7 +2070,7 @@ treeview_button_press (GtkTreeView    *treeview,
                        WindowPlugin   *plugin)
 {
     GtkTreeSelection *selection;
-    GtkTreePath *path = NULL;
+    GtkTreePath *path = nullptr;
     GList *selected;
     int x, y;
 
@@ -2078,7 +2078,7 @@ treeview_button_press (GtkTreeView    *treeview,
         return FALSE;
 
     gtk_tree_view_get_path_at_pos (treeview, (int) event->x, (int) event->y,
-                                   &path, NULL, &x, &y);
+                                   &path, nullptr, &x, &y);
 
     selection = gtk_tree_view_get_selection (treeview);
 
@@ -2087,13 +2087,13 @@ treeview_button_press (GtkTreeView    *treeview,
     else if (!gtk_tree_selection_path_is_selected (selection, path))
         gtk_tree_view_set_cursor (treeview, path, plugin->column, FALSE);
 
-    selected = gtk_tree_selection_get_selected_rows (selection, NULL);
+    selected = gtk_tree_selection_get_selected_rows (selection, nullptr);
     popup_menu (plugin, selected, event->button, event->time);
 
     if (path)
         gtk_tree_path_free (path);
 
-    g_list_foreach (selected, (GFunc) gtk_tree_path_free, NULL);
+    g_list_foreach (selected, (GFunc) gtk_tree_path_free, nullptr);
     g_list_free (selected);
 
     return TRUE;
@@ -2106,7 +2106,7 @@ treeview_row_activated (WindowPlugin *plugin,
     Item *item;
 
     item = get_item_at_path (plugin->list, path);
-    g_return_if_fail (item != NULL);
+    g_return_if_fail (item != nullptr);
 
     if (ITEM_IS_FILE (item))
         open_file (plugin, path);
@@ -2126,10 +2126,10 @@ create_treeview (WindowPlugin *plugin)
     gtk_tree_view_set_headers_visible (plugin->treeview, FALSE);
     gtk_tree_view_set_row_separator_func (plugin->treeview,
                                           (GtkTreeViewRowSeparatorFunc) row_separator_func,
-                                          NULL, NULL);
+                                          nullptr, nullptr);
     gtk_tree_view_set_search_equal_func (plugin->treeview,
                                          (GtkTreeViewSearchEqualFunc) tree_view_search_equal_func,
-                                         NULL, NULL);
+                                         nullptr, nullptr);
     gtk_tree_view_set_tooltip_column (plugin->treeview, COLUMN_TOOLTIP);
 
     selection = gtk_tree_view_get_selection (plugin->treeview);
@@ -2163,13 +2163,13 @@ create_treeview (WindowPlugin *plugin)
     gtk_tree_view_column_pack_start (plugin->column, cell, FALSE);
     gtk_tree_view_column_set_cell_data_func (plugin->column, cell,
                                              (GtkTreeCellDataFunc) pixbuf_data_func,
-                                             NULL, NULL);
+                                             nullptr, nullptr);
 
     plugin->text_cell = gtk_cell_renderer_text_new ();
     gtk_tree_view_column_pack_start (plugin->column, plugin->text_cell, TRUE);
     gtk_tree_view_column_set_cell_data_func (plugin->column, plugin->text_cell,
                                              (GtkTreeCellDataFunc) text_data_func,
-                                             NULL, NULL);
+                                             nullptr, nullptr);
     g_signal_connect (plugin->text_cell, "edited",
                       G_CALLBACK (text_cell_edited), plugin);
     g_signal_connect (plugin->text_cell, "editing-canceled",
@@ -2179,7 +2179,7 @@ create_treeview (WindowPlugin *plugin)
 static void
 create_model (WindowPlugin *plugin)
 {
-    plugin->list = (FileList*) g_object_new (file_list_get_type (), (const char*) NULL);
+    plugin->list = (FileList*) g_object_new (file_list_get_type (), (const char*) nullptr);
     plugin->list->plugin = plugin;
 
     file_list_load_config (plugin->list, plugin->filename, &plugin->ui_config);
@@ -2218,7 +2218,7 @@ do_update (WindowPlugin *plugin)
 
     docs = moo_edit_window_get_docs (MOO_WIN_PLUGIN (plugin)->window);
 
-    for (i = 0, list = NULL; i < docs->n_elms; ++i)
+    for (i = 0, list = nullptr; i < docs->n_elms; ++i)
         list = g_slist_prepend (list, docs->elms[i]);
 
     list = g_slist_sort (list, (GCompareFunc) compare_docs_by_name);
@@ -2233,7 +2233,7 @@ do_update (WindowPlugin *plugin)
 static void
 window_plugin_queue_update (WindowPlugin *plugin)
 {
-    g_return_if_fail (plugin != NULL);
+    g_return_if_fail (plugin != nullptr);
 
     if (!plugin->update_idle)
         plugin->update_idle = g_idle_add ((GSourceFunc) do_update,
@@ -2250,7 +2250,7 @@ load_ui_config (WindowPlugin *plugin)
     {
         UIConfig *cfg = plugin->ui_config;
 
-        plugin->ui_config = NULL;
+        plugin->ui_config = nullptr;
 
         while (cfg->expanded_rows)
         {
@@ -2262,7 +2262,7 @@ load_ui_config (WindowPlugin *plugin)
         }
 
         if (cfg->selected_row)
-            gtk_tree_view_set_cursor (plugin->treeview, cfg->selected_row, NULL, FALSE);
+            gtk_tree_view_set_cursor (plugin->treeview, cfg->selected_row, nullptr, FALSE);
         else
             _moo_tree_view_select_first (plugin->treeview);
 
@@ -2316,7 +2316,7 @@ do_update_ui (WindowPlugin *plugin)
 static void
 window_plugin_queue_update_ui (WindowPlugin *plugin)
 {
-    g_return_if_fail (plugin != NULL);
+    g_return_if_fail (plugin != nullptr);
     if (!plugin->update_ui_idle)
         plugin->update_ui_idle = g_idle_add ((GSourceFunc) do_update_ui,
                                              plugin);
@@ -2339,14 +2339,14 @@ file_list_window_plugin_create (WindowPlugin *plugin)
     create_treeview (plugin);
     create_model (plugin);
 
-    scrolled_window = gtk_scrolled_window_new (NULL, NULL);
+    scrolled_window = gtk_scrolled_window_new (nullptr, nullptr);
     gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_window),
                                     GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
     gtk_container_add (GTK_CONTAINER (scrolled_window), GTK_WIDGET (plugin->treeview));
     gtk_widget_show_all (scrolled_window);
 
     label = moo_pane_label_new (GTK_STOCK_DIRECTORY,
-                                NULL, _("File List"),
+                                nullptr, _("File List"),
                                 _("File List"));
     moo_edit_window_add_pane (window,
                               FILE_LIST_PLUGIN_ID,
@@ -2355,7 +2355,7 @@ file_list_window_plugin_create (WindowPlugin *plugin)
     moo_pane_label_free (label);
 
     pane = moo_big_paned_find_pane (window->paned,
-                                    GTK_WIDGET (scrolled_window), NULL);
+                                    GTK_WIDGET (scrolled_window), nullptr);
     moo_pane_set_drag_dest (pane);
 
     plugin->first_time_show = TRUE;
@@ -2409,7 +2409,7 @@ MOO_PLUGIN_DEFINE_INFO (file_list,
                         MOO_VERSION)
 MOO_WIN_PLUGIN_DEFINE (FileList, file_list)
 MOO_PLUGIN_DEFINE (FileList, file_list,
-                   NULL, NULL, NULL, NULL, NULL,
+                   nullptr, nullptr, nullptr, nullptr, nullptr,
                    file_list_window_plugin_get_type (), 0)
 
 
diff --git a/moo/plugins/moofileselector-prefs.cpp b/moo/plugins/moofileselector-prefs.cpp
index 08a98fa7..185ac93d 100644
--- a/moo/plugins/moofileselector-prefs.cpp
+++ b/moo/plugins/moofileselector-prefs.cpp
@@ -86,7 +86,7 @@ _moo_file_selector_prefs_page (MooPlugin *plugin)
 
     cell = gtk_cell_renderer_text_new ();
     gtk_tree_view_column_pack_start (column, cell, TRUE);
-    gtk_tree_view_column_set_attributes (column, cell, "text", COLUMN_LABEL, NULL);
+    gtk_tree_view_column_set_attributes (column, cell, "text", COLUMN_LABEL, nullptr);
 
     store = gtk_list_store_new (N_COLUMNS, G_TYPE_STRING, G_TYPE_STRING,
                                 G_TYPE_STRING, G_TYPE_STRING);
diff --git a/moo/plugins/moofileselector.cpp b/moo/plugins/moofileselector.cpp
index b626edf4..86e84858 100644
--- a/moo/plugins/moofileselector.cpp
+++ b/moo/plugins/moofileselector.cpp
@@ -162,7 +162,7 @@ _moo_file_selector_class_init (MooFileSelectorClass *klass)
                         G_OBJECT_CLASS_TYPE (klass),
                         G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
                         G_CALLBACK (goto_current_doc_dir),
-                        NULL, NULL,
+                        nullptr, nullptr,
                         _moo_marshal_VOID__VOID,
                         G_TYPE_NONE, 0);
 }
@@ -238,7 +238,7 @@ file_selector_go_home (MooFileView *fileview)
 
     dir = moo_prefs_get_filename (PREFS_LAST_DIR);
 
-    if (!dir || !moo_file_view_chdir_path (fileview, dir, NULL))
+    if (!dir || !moo_file_view_chdir_path (fileview, dir, nullptr))
         g_signal_emit_by_name (fileview, "go-home");
 }
 
@@ -254,8 +254,8 @@ moo_file_selector_chdir (MooFileView    *fileview,
 
     if (result)
     {
-        char *new_dir = NULL;
-        g_object_get (fileview, "current-directory", &new_dir, NULL);
+        char *new_dir = nullptr;
+        g_object_get (fileview, "current-directory", &new_dir, nullptr);
         moo_prefs_set_filename (PREFS_LAST_DIR, new_dir);
         g_free (new_dir);
     }
@@ -273,7 +273,7 @@ moo_file_selector_activate (MooFileView    *fileview,
     gboolean is_text = TRUE, is_exe = FALSE;
     mgw_errno_t err;
 
-    g_return_if_fail (path != NULL);
+    g_return_if_fail (path != nullptr);
 
     if (mgw_stat (path, &statbuf, &err) != 0)
     {
@@ -306,7 +306,7 @@ moo_file_selector_activate (MooFileView    *fileview,
 
     if (is_text)
         moo_editor_open_path (moo_edit_window_get_editor (filesel->window),
-                              path, NULL, -1, filesel->window);
+                              path, nullptr, -1, filesel->window);
     else if (!is_exe)
         moo_open_file (path);
 }
@@ -317,11 +317,11 @@ goto_current_doc_dir (MooFileSelector *filesel)
 {
     MooEdit *doc;
     GFile *file, *parent_file;
-    GError *error = NULL;
+    GError *error = nullptr;
 
     doc = moo_edit_window_get_active_doc (filesel->window);
-    file = doc ? moo_edit_get_file (doc) : NULL;
-    parent_file = file ? g_file_get_parent (file) : NULL;
+    file = doc ? moo_edit_get_file (doc) : nullptr;
+    parent_file = file ? g_file_get_parent (file) : nullptr;
 
     if (parent_file)
     {
@@ -375,7 +375,7 @@ create_new_file_dialog (GtkWidget         *parent,
     char *display_dirname, *label_text;
 
     display_dirname = g_filename_display_basename (dirname);
-    g_return_val_if_fail (display_dirname != NULL, NULL);
+    g_return_val_if_fail (display_dirname != nullptr, nullptr);
 
     *xml = new_file_dialog_xml_new ();
     dialog = GTK_WIDGET ((*xml)->NewFileDialog);
@@ -403,12 +403,12 @@ new_file_dialog (GtkWidget   *parent,
                  const char  *dirname,
                  const char  *start_name)
 {
-    NewFileDialogXml *xml = NULL;
-    GtkWidget *dialog = NULL;
-    GtkEntry *entry = NULL;
-    char *fullname = NULL;
+    NewFileDialogXml *xml = nullptr;
+    GtkWidget *dialog = nullptr;
+    GtkEntry *entry = nullptr;
+    char *fullname = nullptr;
 
-    g_return_val_if_fail (dirname != NULL, NULL);
+    g_return_val_if_fail (dirname != nullptr, nullptr);
 
     while (TRUE)
     {
@@ -419,7 +419,7 @@ new_file_dialog (GtkWidget   *parent,
         if (!dialog)
         {
             dialog = create_new_file_dialog (parent, dirname, start_name, &xml);
-            g_return_val_if_fail (dialog != NULL, NULL);
+            g_return_val_if_fail (dialog != nullptr, nullptr);
             entry = GTK_ENTRY (xml->entry);
         }
 
@@ -435,7 +435,7 @@ new_file_dialog (GtkWidget   *parent,
         }
 
         /* XXX error checking, you know */
-        name = g_filename_from_utf8 (text, -1, NULL, NULL, NULL);
+        name = g_filename_from_utf8 (text, -1, nullptr, nullptr, nullptr);
 
         if (!name)
         {
@@ -450,18 +450,18 @@ new_file_dialog (GtkWidget   *parent,
             continue;
         }
 
-        fullname = g_build_filename (dirname, name, NULL);
+        fullname = g_build_filename (dirname, name, nullptr);
         g_free (name);
 
         if (!g_file_test (fullname, G_FILE_TEST_EXISTS))
             goto out;
 
         err_text = g_strdup_printf (_("File '%s' already exists"), text);
-        moo_error_dialog (err_text, NULL, dialog);
+        moo_error_dialog (err_text, nullptr, dialog);
         g_free (err_text);
 
         g_free (fullname);
-        fullname = NULL;
+        fullname = nullptr;
     }
 
 out:
@@ -474,9 +474,9 @@ out:
 static void
 file_selector_create_file (MooFileSelector *filesel)
 {
-    char *path = NULL, *dir = NULL;
+    char *path = nullptr, *dir = nullptr;
     MooEdit *doc;
-    GList *selected = NULL;
+    GList *selected = nullptr;
     MooOpenInfo *info;
 
     selected = _moo_file_view_get_filenames (MOO_FILE_VIEW (filesel));
@@ -491,18 +491,18 @@ file_selector_create_file (MooFileSelector *filesel)
 
         dir = (char*) selected->data;
         g_list_free (selected);
-        selected = NULL;
+        selected = nullptr;
 
         if (!g_file_test (dir, G_FILE_TEST_IS_DIR))
         {
             g_free (dir);
-            dir = NULL;
+            dir = nullptr;
         }
     }
 
     if (!dir)
     {
-        g_object_get (filesel, "current-directory", &dir, NULL);
+        g_object_get (filesel, "current-directory", &dir, nullptr);
 
         if (!dir)
             goto out;
@@ -513,18 +513,18 @@ file_selector_create_file (MooFileSelector *filesel)
     if (!path)
         goto out;
 
-    info = moo_open_info_new (path, NULL, -1, MOO_OPEN_FLAGS_NONE);
+    info = moo_open_info_new (path, nullptr, -1, MOO_OPEN_FLAGS_NONE);
     doc = moo_editor_new_file (moo_edit_window_get_editor (filesel->window),
-                               info, GTK_WIDGET (filesel), NULL);
+                               info, GTK_WIDGET (filesel), nullptr);
     g_object_unref (info);
 
     if (doc)
-        moo_edit_save (doc, NULL);
+        moo_edit_save (doc, nullptr);
 
 out:
     g_free (path);
     g_free (dir);
-    g_list_foreach (selected, (GFunc) g_free, NULL);
+    g_list_foreach (selected, (GFunc) g_free, nullptr);
     g_list_free (selected);
 }
 
@@ -532,8 +532,8 @@ out:
 static void
 file_selector_open_files (MooFileSelector *filesel)
 {
-    GList *selected = NULL;
-    GList *files = NULL;
+    GList *selected = nullptr;
+    GList *files = nullptr;
 
     selected = _moo_file_view_get_filenames (MOO_FILE_VIEW (filesel));
 
@@ -560,7 +560,7 @@ file_selector_open_files (MooFileSelector *filesel)
     while (files)
     {
         moo_editor_open_path (moo_edit_window_get_editor (filesel->window),
-                              (const char*) files->data, NULL, -1, filesel->window);
+                              (const char*) files->data, nullptr, -1, filesel->window);
         g_free (files->data);
         files = g_list_delete_link (files, files);
     }
@@ -570,7 +570,7 @@ static void
 notify_show_hidden_files (MooFileSelector *filesel)
 {
     gboolean show = FALSE;
-    g_object_get (filesel, "show-hidden-files", &show, NULL);
+    g_object_get (filesel, "show-hidden-files", &show, nullptr);
     moo_prefs_set_bool (PREFS_HIDDEN_FILES, show);
 }
 
@@ -596,14 +596,14 @@ moo_file_selector_constructor (GType           type,
     filesel = MOO_FILE_SELECTOR (object);
     fileview = MOO_FILE_VIEW (object);
 
-    g_return_val_if_fail (filesel->window != NULL, object);
+    g_return_val_if_fail (filesel->window != nullptr, object);
 
     file_selector_go_home (MOO_FILE_VIEW (fileview));
 
-    g_object_set (fileview, "show-hidden-files", moo_prefs_get_bool (PREFS_HIDDEN_FILES), NULL);
-    g_signal_connect (fileview, "notify::show-hidden-files", G_CALLBACK (notify_show_hidden_files), NULL);
+    g_object_set (fileview, "show-hidden-files", moo_prefs_get_bool (PREFS_HIDDEN_FILES), nullptr);
+    g_signal_connect (fileview, "notify::show-hidden-files", G_CALLBACK (notify_show_hidden_files), nullptr);
 
-    group = moo_action_collection_get_group (moo_file_view_get_actions (MOO_FILE_VIEW (fileview)), NULL);
+    group = moo_action_collection_get_group (moo_file_view_get_actions (MOO_FILE_VIEW (fileview)), nullptr);
     xml = moo_file_view_get_ui_xml (MOO_FILE_VIEW (fileview));
     merge_id = moo_ui_xml_new_merge_id (xml);
 
@@ -612,7 +612,7 @@ moo_file_selector_constructor (GType           type,
                                  "tooltip", _("Go to current document directory"),
                                  "closure-object", fileview,
                                  "closure-signal", "goto-current-doc-dir",
-                                 NULL);
+                                 nullptr);
     moo_ui_xml_insert_markup (xml, merge_id,
                               "MooFileView/Toolbar", -1,
                               "<item action=\"GoToCurrentDocDir\"/>");
@@ -626,14 +626,14 @@ moo_file_selector_constructor (GType           type,
                                  "stock-id", GTK_STOCK_NEW,
                                  "closure-object", filesel,
                                  "closure-callback", file_selector_create_file,
-                                 NULL);
+                                 nullptr);
     moo_action_group_add_action (group, "Open",
                                  "label", GTK_STOCK_OPEN,
                                  "tooltip", GTK_STOCK_OPEN,
                                  "stock-id", GTK_STOCK_OPEN,
                                  "closure-object", filesel,
                                  "closure-callback", file_selector_open_files,
-                                 NULL);
+                                 nullptr);
     moo_ui_xml_insert_markup_before (xml, merge_id,
                                      "MooFileView/Menu",
                                      "NewFolder",
@@ -644,14 +644,14 @@ moo_file_selector_constructor (GType           type,
                               "<item action=\"Open\"/>");
 
     label = moo_pane_label_new (MOO_STOCK_FILE_SELECTOR,
-                                NULL, _("File Selector"),
+                                nullptr, _("File Selector"),
                                 _("File Selector"));
     moo_edit_window_add_pane (filesel->window, MOO_FILE_SELECTOR_PLUGIN_ID,
                               GTK_WIDGET (filesel), label, MOO_PANE_POS_RIGHT);
     moo_pane_label_free (label);
 
     pane = moo_big_paned_find_pane (filesel->window->paned,
-                                    GTK_WIDGET (filesel), NULL);
+                                    GTK_WIDGET (filesel), nullptr);
     moo_pane_set_drag_dest (pane);
 
     return object;
@@ -773,12 +773,12 @@ save_as_dialog (GtkWidget   *parent,
                 gboolean     ask_name,
                 const char  *title)
 {
-    SaveAsDialogXml *xml = NULL;
-    GtkWidget *dialog = NULL;
-    GtkEntry *entry = NULL;
-    char *fullname = NULL;
+    SaveAsDialogXml *xml = nullptr;
+    GtkWidget *dialog = nullptr;
+    GtkEntry *entry = nullptr;
+    char *fullname = nullptr;
 
-    g_return_val_if_fail (dirname != NULL, NULL);
+    g_return_val_if_fail (dirname != nullptr, nullptr);
 
     while (TRUE)
     {
@@ -811,7 +811,7 @@ save_as_dialog (GtkWidget   *parent,
         }
 
         /* XXX error checking, you know */
-        name = g_filename_from_utf8 (text, -1, NULL, NULL, NULL);
+        name = g_filename_from_utf8 (text, -1, nullptr, nullptr, nullptr);
 
         if (!name)
         {
@@ -826,7 +826,7 @@ save_as_dialog (GtkWidget   *parent,
             continue;
         }
 
-        fullname = g_build_filename (dirname, name, NULL);
+        fullname = g_build_filename (dirname, name, nullptr);
         g_free (name);
 
         if (!g_file_test (fullname, G_FILE_TEST_EXISTS))
@@ -842,7 +842,7 @@ save_as_dialog (GtkWidget   *parent,
 
         g_free (display_dirname);
         g_free (fullname);
-        fullname = NULL;
+        fullname = nullptr;
     }
 
 out:
@@ -858,7 +858,7 @@ moo_file_selector_select_path (MooFileSelector *filesel,
 {
     char *basename;
 
-    g_return_if_fail (filename != NULL);
+    g_return_if_fail (filename != nullptr);
 
     basename = g_path_get_basename (filename);
     _moo_file_view_select_name (MOO_FILE_VIEW (filesel), basename);
@@ -882,8 +882,8 @@ save_as_path (MooEdit    *doc,
 {
     MooSaveInfo *info;
     gboolean result;
-    info = moo_save_info_new (path, NULL);
-    result = moo_edit_save_as (doc, info, NULL);
+    info = moo_save_info_new (path, nullptr);
+    result = moo_edit_save_as (doc, info, nullptr);
     g_object_unref (info);
     return result;
 }
@@ -953,8 +953,8 @@ doc_save_copy (MooFileSelector *filesel,
 
     if (filename)
     {
-        MooSaveInfo *info = moo_save_info_new (filename, NULL);
-        if (moo_edit_save_copy (doc, info, NULL))
+        MooSaveInfo *info = moo_save_info_new (filename, nullptr);
+        if (moo_edit_save_copy (doc, info, nullptr))
             moo_file_selector_select_path (filesel, filename);
         g_object_unref (info);
         g_free (filename);
@@ -971,7 +971,7 @@ doc_move (MooFileSelector *filesel,
     char *filename;
 
     old_file = moo_edit_get_file (doc);
-    g_return_if_fail (old_file != NULL);
+    g_return_if_fail (old_file != nullptr);
 
     filename = save_as_dialog (GTK_WIDGET (filesel), destdir,
                                moo_edit_get_display_basename (doc),
@@ -981,7 +981,7 @@ doc_move (MooFileSelector *filesel,
     {
         if (save_as_path (doc, filename))
         {
-            g_file_delete (old_file, NULL, NULL);
+            g_file_delete (old_file, nullptr, nullptr);
             moo_file_selector_select_path (filesel, filename);
         }
 
@@ -1014,7 +1014,7 @@ drop_item_activated (GObject         *item,
     doc = (MooEdit*) g_object_get_data (item, "moo-file-selector-drop-doc");
     destdir = (char*) g_object_get_data (item, "moo-file-selector-drop-destdir");
     alternate = GPOINTER_TO_INT (g_object_get_data (item, "moo-menu-item-alternate"));
-    g_return_if_fail (doc != NULL && destdir != NULL);
+    g_return_if_fail (doc != nullptr && destdir != nullptr);
 
     action = (DropDocAction) GPOINTER_TO_INT (data);
 
@@ -1086,7 +1086,7 @@ alternate_toggled (GtkWidget *menu)
 
     items = (GSList*) g_object_get_data (G_OBJECT (menu), "moo-menu-items");
 
-    for (l = items; l != NULL; l = l->next)
+    for (l = items; l != nullptr; l = l->next)
     {
         GtkWidget *item = (GtkWidget*) l->data;
         const char *label;
@@ -1108,10 +1108,10 @@ create_drop_doc_menu (MooFileSelector *filesel,
                       const char      *destdir)
 {
     GtkWidget *menu, *item;
-    GSList *items = NULL;
+    GSList *items = nullptr;
 
     menu = moo_menu_new ();
-    g_signal_connect (menu, "alternate-toggled", G_CALLBACK (alternate_toggled), NULL);
+    g_signal_connect (menu, "alternate-toggled", G_CALLBACK (alternate_toggled), nullptr);
 
     item = create_menu_item (filesel, doc, destdir,
                              MOO_STOCK_FILE_MOVE,
@@ -1147,7 +1147,7 @@ create_drop_doc_menu (MooFileSelector *filesel,
     gtk_widget_show (item);
     gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
 
-    item = gtk_image_menu_item_new_from_stock (GTK_STOCK_CANCEL, NULL);
+    item = gtk_image_menu_item_new_from_stock (GTK_STOCK_CANCEL, nullptr);
     gtk_widget_show (item);
     _moo_menu_item_set_accel_label (item, "Escape");
     gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
@@ -1170,7 +1170,7 @@ moo_file_selector_drop_doc (MooFileSelector *filesel,
     DropDocAction action;
 
     g_return_if_fail (MOO_IS_EDIT (doc));
-    g_return_if_fail (destdir != NULL);
+    g_return_if_fail (destdir != nullptr);
     g_return_if_fail (GTK_IS_WIDGET (widget));
 
     if (moo_edit_is_untitled (doc))
@@ -1197,7 +1197,7 @@ moo_file_selector_drop_doc (MooFileSelector *filesel,
         GtkWidget *menu = create_drop_doc_menu (filesel, doc, destdir);
         g_object_ref_sink (menu);
         _moo_file_view_drag_finish (MOO_FILE_VIEW (filesel), context, TRUE, FALSE, time);
-        gtk_menu_popup (GTK_MENU (menu), NULL, NULL, NULL, NULL, 0, 0);
+        gtk_menu_popup (GTK_MENU (menu), nullptr, nullptr, nullptr, nullptr, 0, 0);
         g_object_unref (menu);
         return;
     }
@@ -1228,7 +1228,7 @@ moo_file_selector_drop_doc (MooFileSelector *filesel,
 static gboolean
 file_selector_plugin_init (G_GNUC_UNUSED Plugin *plugin)
 {
-    moo_prefs_create_key (PREFS_LAST_DIR, MOO_PREFS_STATE, G_TYPE_STRING, NULL);
+    moo_prefs_create_key (PREFS_LAST_DIR, MOO_PREFS_STATE, G_TYPE_STRING, nullptr);
     moo_prefs_create_key (PREFS_HIDDEN_FILES, MOO_PREFS_RC, G_TYPE_BOOLEAN, FALSE);
     return TRUE;
 }
@@ -1239,7 +1239,7 @@ file_selector_plugin_deinit (Plugin *plugin)
 {
     if (plugin->bookmark_mgr)
         g_object_unref (plugin->bookmark_mgr);
-    plugin->bookmark_mgr = NULL;
+    plugin->bookmark_mgr = nullptr;
 }
 
 
@@ -1258,7 +1258,7 @@ file_selector_plugin_attach (MooPlugin     *mplugin,
         g_object_new (MOO_TYPE_FILE_SELECTOR,
                       "bookmark-mgr", plugin->bookmark_mgr,
                       "window", window,
-                      (const char*) NULL));
+                      (const char*) nullptr));
 
     plugin->instances = g_slist_prepend (plugin->instances, filesel);
 }
@@ -1271,7 +1271,7 @@ file_selector_plugin_detach (MooPlugin     *mplugin,
     Plugin *plugin = FILE_SELECTOR_PLUGIN (mplugin);
     GtkWidget *filesel = moo_edit_window_get_pane (window, MOO_FILE_SELECTOR_PLUGIN_ID);
 
-    g_return_if_fail (filesel != NULL);
+    g_return_if_fail (filesel != nullptr);
 
     plugin->instances = g_slist_remove (plugin->instances, filesel);
     moo_edit_window_remove_pane (window, MOO_FILE_SELECTOR_PLUGIN_ID);
@@ -1282,7 +1282,7 @@ void
 _moo_file_selector_update_tools (MooPlugin *plugin)
 {
     GSList *l;
-    for (l = ((Plugin*)plugin)->instances; l != NULL; l = l->next)
+    for (l = ((Plugin*)plugin)->instances; l != nullptr; l = l->next)
         _moo_file_view_tools_load ((MooFileView*) l->data);
 }
 
@@ -1294,7 +1294,7 @@ MOO_PLUGIN_DEFINE_INFO (file_selector,
                         MOO_VERSION)
 MOO_PLUGIN_DEFINE (FileSelector, file_selector,
                    file_selector_plugin_attach, file_selector_plugin_detach,
-                   NULL, NULL,
+                   nullptr, nullptr,
                    _moo_file_selector_prefs_page,
                    0, 0)
 
@@ -1304,7 +1304,7 @@ get_widget_meth (G_GNUC_UNUSED gpointer plugin,
                  MooEditWindow *window)
 {
     gpointer widget = moo_edit_window_get_pane (window, MOO_FILE_SELECTOR_PLUGIN_ID);
-    return widget ? g_object_ref (widget) : NULL;
+    return widget ? g_object_ref (widget) : nullptr;
 }
 
 
@@ -1316,7 +1316,7 @@ _moo_file_selector_plugin_init (void)
     if (!moo_plugin_register (MOO_FILE_SELECTOR_PLUGIN_ID,
                               ptype,
                               &file_selector_plugin_info,
-                              NULL))
+                              nullptr))
         return FALSE;
 
     moo_plugin_method_new ("get-widget", ptype,
diff --git a/moo/plugins/moofind.cpp b/moo/plugins/moofind.cpp
index f20befdb..d52f5eb2 100644
--- a/moo/plugins/moofind.cpp
+++ b/moo/plugins/moofind.cpp
@@ -206,7 +206,7 @@ ensure_output (WindowStuff *stuff)
                                       "foreground", "#008040", NULL);
     stuff->error_tag =
             moo_text_view_lookup_tag (MOO_TEXT_VIEW (stuff->output), "error");
-    g_object_set (stuff->error_tag, "foreground", "#C00000", NULL);
+    g_object_set (stuff->error_tag, "foreground", "#C00000", nullptr);
 
     stuff->message_tag =
             moo_text_view_lookup_tag (MOO_TEXT_VIEW (stuff->output), "message");
@@ -255,7 +255,7 @@ find_plugin_init (FindPlugin *plugin)
                                  "default-accel", MOO_EDIT_ACCEL_FIND_IN_FILES,
                                  "stock-id", MOO_STOCK_FIND_IN_FILES,
                                  "closure-callback", find_in_files_cb,
-                                 NULL);
+                                 nullptr);
 
 #ifndef __WIN32__
     moo_window_class_new_action (klass, "FindFile", NULL,
@@ -264,7 +264,7 @@ find_plugin_init (FindPlugin *plugin)
                                  "tooltip", _("Find file"),
                                  "stock-id", MOO_STOCK_FIND_FILE,
                                  "closure-callback", find_file_cb,
-                                 NULL);
+                                 nullptr);
 #endif
 
     if (xml)
@@ -321,7 +321,7 @@ setup_file_combo (MooHistoryCombo *hist_combo)
     GtkWidget *entry;
     MooFileEntryCompletion *completion;
 
-    g_object_set (hist_combo, "enable-completion", FALSE, NULL);
+    g_object_set (hist_combo, "enable-completion", FALSE, nullptr);
 
     entry = MOO_COMBO (hist_combo)->entry;
     completion = MOO_FILE_ENTRY_COMPLETION (
diff --git a/moo/plugins/support/moocmdview.cpp b/moo/plugins/support/moocmdview.cpp
index cf6c5432..002723fa 100644
--- a/moo/plugins/support/moocmdview.cpp
+++ b/moo/plugins/support/moocmdview.cpp
@@ -181,8 +181,8 @@ moo_cmd_view_constructor (GType                  type,
     view->priv->stdout_tag = gtk_text_buffer_create_tag (buffer, "stdout", NULL);
     view->priv->stderr_tag = gtk_text_buffer_create_tag (buffer, "stderr", NULL);
 
-    g_object_set (view->priv->error_tag, "foreground", "red", NULL);
-    g_object_set (view->priv->stderr_tag, "foreground", "red", NULL);
+    g_object_set (view->priv->error_tag, "foreground", "red", nullptr);
+    g_object_set (view->priv->stderr_tag, "foreground", "red", nullptr);
 
     return object;
 }
diff --git a/moo/plugins/support/moocmdview.h b/moo/plugins/support/moocmdview.h
index 2baa4c8e..faa1a5a2 100644
--- a/moo/plugins/support/moocmdview.h
+++ b/moo/plugins/support/moocmdview.h
@@ -36,13 +36,16 @@ G_BEGIN_DECLS
 
 typedef struct _MooCmdViewPrivate  MooCmdViewPrivate;
 
-struct MooCmdView : public MooLineView
+struct MooCmdView
 {
+    MooLineView parent;
     MooCmdViewPrivate *priv;
 };
 
-struct MooCmdViewClass : public MooLineViewClass
+struct MooCmdViewClass
 {
+    MooLineViewClass parent_class;
+
     void     (*job_started) (MooCmdView *view,
                              const char *job_name);
     void     (*job_finished)(MooCmdView *view);
diff --git a/moo/plugins/support/moolineview.cpp b/moo/plugins/support/moolineview.cpp
index 183ce6a0..5033b407 100644
--- a/moo/plugins/support/moolineview.cpp
+++ b/moo/plugins/support/moolineview.cpp
@@ -138,7 +138,7 @@ moo_line_view_init (MooLineView *view)
                   "cursor-visible", FALSE,
                   "current-line-color", "grey",
                   "highlight-matching-brackets", FALSE,
-                  NULL);
+                  nullptr);
 }
 
 
@@ -527,7 +527,7 @@ check_if_scrolled (MooLineView *view)
     if (view->priv->hscrollbar && GTK_WIDGET_VISIBLE (view->priv->hscrollbar))
     {
         int space;
-        gtk_widget_style_get (GTK_WIDGET (view)->parent, "scrollbar-spacing", &space, NULL);
+        gtk_widget_style_get (GTK_WIDGET (view)->parent, "scrollbar-spacing", &space, nullptr);
         delta = MAX (delta - 1, space + view->priv->hscrollbar->allocation.height) + 1;
     }
 
@@ -578,14 +578,14 @@ moo_line_view_write (MooLineView    *view,
 
     if (g_utf8_validate (text, len, NULL))
     {
-        gtk_text_buffer_insert_with_tags (buffer, &iter, text, len, tag, NULL);
+        gtk_text_buffer_insert_with_tags (buffer, &iter, text, len, tag, nullptr);
     }
     else
     {
         char *text_utf8 = g_locale_to_utf8 (text, len, NULL, NULL, NULL);
 
         if (text_utf8)
-            gtk_text_buffer_insert_with_tags (buffer, &iter, text_utf8, -1, tag, NULL);
+            gtk_text_buffer_insert_with_tags (buffer, &iter, text_utf8, -1, tag, nullptr);
         else
             g_warning ("could not convert '%s' to utf8", text);
 
diff --git a/moo/plugins/support/moolineview.h b/moo/plugins/support/moolineview.h
index 492bbb66..9a897fd0 100644
--- a/moo/plugins/support/moolineview.h
+++ b/moo/plugins/support/moolineview.h
@@ -32,13 +32,16 @@ G_BEGIN_DECLS
 
 typedef struct _MooLineViewPrivate  MooLineViewPrivate;
 
-struct MooLineView : public MooTextView
+struct MooLineView
 {
+    MooTextView parent;
     MooLineViewPrivate *priv;
 };
 
-struct MooLineViewClass : public MooTextViewClass
+struct MooLineViewClass
 {
+    MooTextViewClass parent_class;
+
     void     (*activate) (MooLineView *view,
                           int          line);
 };
diff --git a/moo/plugins/support/moooutputfilter.cpp b/moo/plugins/support/moooutputfilter.cpp
index 5c0066bc..2017a92c 100644
--- a/moo/plugins/support/moooutputfilter.cpp
+++ b/moo/plugins/support/moooutputfilter.cpp
@@ -368,7 +368,7 @@ find_file_in_dirs (const char  *filename,
 {
     for ( ; dirs && *dirs; ++dirs)
     {
-        char *path = g_build_filename (*dirs, filename, NULL);
+        char *path = g_build_filename (*dirs, filename, nullptr);
         if (g_file_test (path, G_FILE_TEST_EXISTS))
             return path;
         g_free (path);
diff --git a/moo/plugins/support/moooutputfilter.h b/moo/plugins/support/moooutputfilter.h
index d36da188..55fbecc2 100644
--- a/moo/plugins/support/moooutputfilter.h
+++ b/moo/plugins/support/moooutputfilter.h
@@ -39,13 +39,16 @@ struct _MooFileLineData {
     int character;
 };
 
-struct MooOutputFilter : public GObject
+struct MooOutputFilter
 {
+    GObject parent;
     MooOutputFilterPrivate *priv;
 };
 
-struct MooOutputFilterClass : public GObjectClass
+struct MooOutputFilterClass
 {
+    GObjectClass parent_class;
+
     void     (*attach)      (MooOutputFilter *filter);
     void     (*detach)      (MooOutputFilter *filter);
 
diff --git a/moo/plugins/usertools/moocommand-exe.cpp b/moo/plugins/usertools/moocommand-exe.cpp
index 3aa09482..9062b115 100644
--- a/moo/plugins/usertools/moocommand-exe.cpp
+++ b/moo/plugins/usertools/moocommand-exe.cpp
@@ -957,7 +957,7 @@ init_combo (GtkComboBox *combo,
 
     cell = gtk_cell_renderer_text_new ();
     gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (combo), cell, TRUE);
-    gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (combo), cell, "text", 0, NULL);
+    gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (combo), cell, "text", 0, nullptr);
 
     store = gtk_list_store_new (1, G_TYPE_STRING);
 
@@ -984,7 +984,7 @@ init_filter_combo (GtkComboBox *combo)
     cell = gtk_cell_renderer_text_new ();
     gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (combo), cell, TRUE);
     gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (combo), cell,
-                                    "text", COLUMN_NAME, NULL);
+                                    "text", COLUMN_NAME, nullptr);
 
     store = gtk_list_store_new (2, G_TYPE_STRING, G_TYPE_STRING);
 
diff --git a/moo/plugins/usertools/moocommanddisplay.cpp b/moo/plugins/usertools/moocommanddisplay.cpp
index c6e762ff..6d7406d2 100644
--- a/moo/plugins/usertools/moocommanddisplay.cpp
+++ b/moo/plugins/usertools/moocommanddisplay.cpp
@@ -223,7 +223,7 @@ init_factory_combo (MooCommandDisplay *display,
 
     cell = gtk_cell_renderer_text_new ();
     gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (display->factory_combo), cell, TRUE);
-    gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (display->factory_combo), cell, "text", 0, NULL);
+    gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (display->factory_combo), cell, "text", 0, nullptr);
 
     store = gtk_list_store_new (1, G_TYPE_STRING);
 
diff --git a/moo/plugins/usertools/moooutputfilterregex.cpp b/moo/plugins/usertools/moooutputfilterregex.cpp
index fc3e8238..c0982ca6 100644
--- a/moo/plugins/usertools/moooutputfilterregex.cpp
+++ b/moo/plugins/usertools/moooutputfilterregex.cpp
@@ -184,7 +184,7 @@ find_file_in_dir (const char *file,
     if (!file || !dir)
         return NULL;
 
-    path = g_build_filename (dir, file, NULL);
+    path = g_build_filename (dir, file, nullptr);
 
     if (g_file_test (path, G_FILE_TEST_EXISTS))
         return path;
@@ -401,7 +401,7 @@ get_tag (MooLineView *view,
             _moo_text_style_apply_to_tag (style, tag);
         else if (type == OUTPUT_STDERR || !strcmp (name, "output-error") ||
                  !strcmp (name, "output-stderr"))
-            g_object_set (tag, "foreground", "red", NULL);
+            g_object_set (tag, "foreground", "red", nullptr);
     }
 
     return tag;
diff --git a/moo/plugins/usertools/moousertools-prefs.cpp b/moo/plugins/usertools/moousertools-prefs.cpp
index 4e002517..09ea84e2 100644
--- a/moo/plugins/usertools/moousertools-prefs.cpp
+++ b/moo/plugins/usertools/moousertools-prefs.cpp
@@ -404,7 +404,7 @@ name_data_func (G_GNUC_UNUSED GtkTreeViewColumn *column,
     gtk_tree_model_get (model, iter, COLUMN_INFO, &info, -1);
     g_return_if_fail (info != NULL);
 
-    g_object_set (cell, "text", info->name, NULL);
+    g_object_set (cell, "text", info->name, nullptr);
 
     _moo_user_tool_info_unref (info);
 }
@@ -466,7 +466,7 @@ command_page_init (MooPrefsPage    *page,
                                              (GtkTreeCellDataFunc) name_data_func,
                                              NULL, NULL);
     gtk_tree_view_append_column (gxml->treeview, column);
-    g_object_set (cell, "editable", TRUE, NULL);
+    g_object_set (cell, "editable", TRUE, nullptr);
     g_signal_connect_swapped (cell, "edited", G_CALLBACK (name_cell_edited), page);
 
     populate_store (store, type);
diff --git a/moo/plugins/usertools/moousertools.cpp b/moo/plugins/usertools/moousertools.cpp
index 13a86bd4..9057f191 100644
--- a/moo/plugins/usertools/moousertools.cpp
+++ b/moo/plugins/usertools/moousertools.cpp
@@ -399,7 +399,7 @@ load_tool (MooUserToolInfo *info)
                                          "label", label,
                                          "default-accel", info->accel,
                                          "command", cmd,
-                                         NULL);
+                                         nullptr);
 
             moo_edit_window_set_action_check (info->id, MOO_ACTION_CHECK_SENSITIVE,
                                               check_sensitive_func,
@@ -417,7 +417,7 @@ load_tool (MooUserToolInfo *info)
                                        "default-accel", info->accel,
                                        "command", cmd,
                                        "file-filter", info->filter,
-                                       NULL);
+                                       nullptr);
             break;
     }
 
@@ -639,7 +639,7 @@ load_directory (const char       *path,
     {
         char *filename;
 
-        filename = g_build_filename (path, names->pdata[i], NULL);
+        filename = g_build_filename (path, names->pdata[i], nullptr);
         load_file (filename, (const char*) names->pdata[i], type, list, ids);
 
         g_free (filename);
@@ -1321,7 +1321,7 @@ moo_tool_action_check_state (MooEditAction *edit_action)
     doc = moo_edit_action_get_doc (edit_action);
     sensitive = moo_command_check_sensitive (action->cmd, doc);
 
-    g_object_set (action, "sensitive", sensitive, NULL);
+    g_object_set (action, "sensitive", sensitive, nullptr);
 }