diff --git a/ChangeLog b/ChangeLog
index 9e804959..85447459 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2007-05-08  Enrico Tröger  <enrico.troeger@uvena.de>
+
+ * src/sciwrappers.c, src/sciwrappers.h:
+   Added sci_get_line_indentation() and sci_set_line_indentation().
+ * src/callbacks.c: Fixed broken increase/decrease indentation when
+                    using only spaces for indentation.
+
+
 2007-05-07  Enrico Tröger  <enrico.troeger@uvena.de>
 
  * data/filetypes.haskell: Added build instructions.
diff --git a/src/callbacks.c b/src/callbacks.c
index ac46d627..91c8f5fd 100644
--- a/src/callbacks.c
+++ b/src/callbacks.c
@@ -1863,7 +1863,7 @@ on_menu_increase_indent1_activate      (GtkMenuItem     *menuitem,
                                         gpointer         user_data)
 {
 	gint idx = document_get_cur_idx();
-	if (idx == -1 || ! doc_list[idx].is_valid) return;
+	if (! DOC_IDX_VALID(idx)) return;
 
 	if (sci_get_lines_selected(doc_list[idx].sci) > 1)
 	{
@@ -1871,16 +1871,18 @@ on_menu_increase_indent1_activate      (GtkMenuItem     *menuitem,
 	}
 	else
 	{
-		gint line, ind_pos, old_pos;
+		gint line, ind_pos, old_pos, new_pos, step;
 
 		old_pos = sci_get_current_position(doc_list[idx].sci);
 		line = sci_get_current_line(doc_list[idx].sci, old_pos);
 		ind_pos = sci_get_line_indent_position(doc_list[idx].sci, line);
+		// when using tabs increase cur pos by 1, when using space increase it by tab_width
+		step = (app->pref_editor_use_tabs) ? 1 : app->pref_editor_tab_width;
+		new_pos = (old_pos > ind_pos) ? old_pos + step : old_pos;
 
 		sci_set_current_position(doc_list[idx].sci, ind_pos, TRUE);
 		sci_cmd(doc_list[idx].sci, SCI_TAB);
-		sci_set_current_position(doc_list[idx].sci,
-			(old_pos > ind_pos) ? old_pos + 1 : old_pos, TRUE);
+		sci_set_current_position(doc_list[idx].sci, new_pos, TRUE);
 	}
 }
 
@@ -1890,7 +1892,7 @@ on_menu_decrease_indent1_activate      (GtkMenuItem     *menuitem,
                                         gpointer         user_data)
 {
 	gint idx = document_get_cur_idx();
-	if (idx == -1 || ! doc_list[idx].is_valid) return;
+	if (! DOC_IDX_VALID(idx)) return;
 
 	if (sci_get_lines_selected(doc_list[idx].sci) > 1)
 	{
@@ -1898,18 +1900,25 @@ on_menu_decrease_indent1_activate      (GtkMenuItem     *menuitem,
 	}
 	else
 	{
-		gint line, ind_pos, old_pos;
+		gint line, ind_pos, old_pos, new_pos, step, indent;
 
 		old_pos = sci_get_current_position(doc_list[idx].sci);
 		line = sci_get_current_line(doc_list[idx].sci, old_pos);
 		ind_pos = sci_get_line_indent_position(doc_list[idx].sci, line);
+		step = (app->pref_editor_use_tabs) ? 1 : app->pref_editor_tab_width;
+		new_pos = (old_pos >= ind_pos) ? old_pos - step : old_pos;
 
 		if (ind_pos == sci_get_position_from_line(doc_list[idx].sci, line))
 			return;
+
 		sci_set_current_position(doc_list[idx].sci, ind_pos, TRUE);
-		sci_cmd(doc_list[idx].sci, SCI_BACKTAB);
-		sci_set_current_position(doc_list[idx].sci,
-			(old_pos >= ind_pos) ? old_pos - 1 : old_pos, TRUE);
+		indent = sci_get_line_indentation(doc_list[idx].sci, line);
+		indent -= app->pref_editor_tab_width;
+		if (indent < 0)
+			indent = 0;
+		sci_set_line_indentation(doc_list[idx].sci, line, indent);
+
+		sci_set_current_position(doc_list[idx].sci, new_pos, TRUE);
 	}
 }
 
diff --git a/src/sciwrappers.c b/src/sciwrappers.c
index 4611a6ad..c37b5c0f 100644
--- a/src/sciwrappers.c
+++ b/src/sciwrappers.c
@@ -941,3 +941,13 @@ void sci_set_scrollbar_mode(ScintillaObject *sci, gboolean visible)
 	SSM(sci, SCI_SETVSCROLLBAR, visible, 0);
 }
 
+void sci_set_line_indentation(ScintillaObject *sci, gint line, gint indent)
+{
+	SSM(sci, SCI_SETLINEINDENTATION, line, indent);
+}
+
+int sci_get_line_indentation(ScintillaObject *sci, gint line)
+{
+	return SSM(sci, SCI_GETLINEINDENTATION, line, 0);
+}
+
diff --git a/src/sciwrappers.h b/src/sciwrappers.h
index 617520a1..c67249d2 100644
--- a/src/sciwrappers.h
+++ b/src/sciwrappers.h
@@ -167,6 +167,8 @@ void				sci_set_styling				(ScintillaObject * sci, gint len, gint style);
 void				sci_start_styling			(ScintillaObject * sci, gint pos, gint mask);
 void				sci_select_all				(ScintillaObject * sci);
 gint				sci_get_line_indent_position(ScintillaObject * sci, gint line);
+void				sci_set_line_indentation	(ScintillaObject * sci, gint line, gint indent);
+int					sci_get_line_indentation	(ScintillaObject * sci, gint line);
 void				sci_set_autoc_max_height	(ScintillaObject * sci, gint val);
 gint				sci_find_bracematch			(ScintillaObject * sci, gint pos);