diff --git a/mods/rp_achievements/init.lua b/mods/rp_achievements/init.lua
index bd2475e..ca14268 100644
--- a/mods/rp_achievements/init.lua
+++ b/mods/rp_achievements/init.lua
@@ -200,7 +200,7 @@ local function check_achievement_gotten(player, aname)
       minetest.log("action", "[rp_achievements] " .. name .. " got achievement '"..aname.."'")
    end
 
-   if rp_formspec.get_invpage(player) == "rp_achievements:achievements" then
+   if rp_formspec.get_current_invpage(player) == "rp_achievements:achievements" then
       local form = achievements.get_formspec(name)
       player:set_inventory_formspec(form)
    end
@@ -440,7 +440,7 @@ function achievements.get_formspec(name, row)
       achievement_list = achievement_list .. minetest.formspec_escape(def.description)
    end
 
-   local form = rp_formspec.get_page("rp_achievements:achievements")
+   local form = rp_formspec.get_page("rp_achievements:achievements", true)
 
    form = form .. "set_focus[achievement_list]"
    form = form .. "table[0.25,2.5;7.9,5.5;achievement_list;" .. achievement_list
diff --git a/mods/rp_armor/init.lua b/mods/rp_armor/init.lua
index 8dafb8a..ff89790 100644
--- a/mods/rp_armor/init.lua
+++ b/mods/rp_armor/init.lua
@@ -41,7 +41,7 @@ form_armor = form_armor .. "listring[current_player;armor]"
 form_armor = form_armor .. rp_formspec.get_itemslot_bg(2.25, 0.75, 1, 3)
 
 function armor.get_formspec(name)
-   local form = rp_formspec.get_page("rp_armor:armor")
+   local form = rp_formspec.get_page("rp_armor:armor", true)
    return form
 end
 
diff --git a/mods/rp_crafting/api.lua b/mods/rp_crafting/api.lua
index 87406d5..2d0dfe5 100644
--- a/mods/rp_crafting/api.lua
+++ b/mods/rp_crafting/api.lua
@@ -382,7 +382,7 @@ function crafting.get_formspec(name, select_craft_id)
       end
    end
 
-   local form = rp_formspec.get_page("rp_crafting:crafting")
+   local form = rp_formspec.get_page("rp_crafting:crafting", true)
 
    if craft_count > 0 then
        form = form .. "table[2.25,0.25;4.75,3.75;craft_list;" .. craft_list
diff --git a/mods/rp_creative/init.lua b/mods/rp_creative/init.lua
index 4d5290e..8b6d6eb 100644
--- a/mods/rp_creative/init.lua
+++ b/mods/rp_creative/init.lua
@@ -250,7 +250,7 @@ creative.get_formspec = function(playername)
 	end
 	local player = minetest.get_player_by_name(playername)
 	if player then
-                local form = rp_formspec.get_page("rp_creative:creative")
+                local form = rp_formspec.get_page("rp_creative:creative", true)
 		local page, start_i = get_page_and_start_i(playername)
 		form = form .. creative.get_creative_formspec(player, start_i, page)
 		return form
@@ -320,7 +320,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		page = 1
 	end
 
-	local form = rp_formspec.get_page("rp_creative:creative")
+	local form = rp_formspec.get_page("rp_creative:creative", true)
 	form = form .. creative.get_creative_formspec(player, start_i, start_i / (creative.slots_num) + 1)
 	if changed then
 		player:set_inventory_formspec(form)
diff --git a/mods/rp_formspec/init.lua b/mods/rp_formspec/init.lua
index 7c8087b..c944227 100644
--- a/mods/rp_formspec/init.lua
+++ b/mods/rp_formspec/init.lua
@@ -273,10 +273,17 @@ function rp_formspec.register_invtab(name, def)
    local rdef = table.copy(def)
    rp_formspec.registered_invtabs[name] = def
    table.insert(registered_invtabs_order, name)
+   invtabs_cached_needs_update = true
 end
 
+local invtabs_cached
+local invtabs_cached_needs_update = true
+
 -- Returns a formspec string for all the inventory tabs
 local function get_invtabs()
+   if not invtabs_cached_needs_update then
+      return invtabs_cached
+   end
    local form = ""
    local tabx = -0.9
    local taby = 0.5
@@ -287,19 +294,23 @@ local function get_invtabs()
       form = form .. rp_formspec.tab(tabx, taby, "_rp_formspec_tab_"..tabname, def.icon, def.tooltip)
       taby = taby + tabplus
    end
+   invtabs_cached = form
    return form
 end
 
 
 -- Pages
 
-function rp_formspec.get_page(name)
+function rp_formspec.get_page(name, with_invtabs)
    local page = rp_formspec.registered_pages[name]
 
    if page == nil then
       minetest.log("warning", "[rp_formspec] UI page '" .. name .. "' is not yet registered")
       return ""
    end
+   if with_invtabs then
+      page = page .. get_invtabs()
+   end
 
    return page
 end
@@ -358,19 +369,15 @@ function rp_formspec.receive_fields(player, form_name, fields)
       end
    end
    if invpagename and form then
-      rp_formspec.set_invpage(player, invpagename)
+      rp_formspec.set_current_invpage(player, invpagename)
    end
 end
 
 function rp_formspec.register_invpage(name, def)
-   local rdef = table.copy(def)
-   if rdef.with_invtabs == nil then
-      rdef.with_invtabs = true
-   end
-   rp_formspec.registered_invpages[name] = rdef
+   rp_formspec.registered_invpages[name] = def
 end
 
-function rp_formspec.set_invpage(player, page)
+function rp_formspec.set_current_invpage(player, page)
     local def = rp_formspec.registered_invpages[page]
     local pname = player:get_player_name()
     local formspec
@@ -379,14 +386,11 @@ function rp_formspec.set_invpage(player, page)
     else
        formspec = rp_formspec.registered_pages[page]
     end
-    if def.with_invtabs then
-       formspec = formspec .. get_invtabs()
-    end
     player:set_inventory_formspec(formspec)
     current_invpage[pname] = page
 end
 
-function rp_formspec.get_invpage(player)
+function rp_formspec.get_current_invpage(player)
     local pname = player:get_player_name()
     return current_invpage[pname]
 end
@@ -405,12 +409,12 @@ minetest.register_on_joinplayer(
       local pname = player:get_player_name()
       for invpagename,def in pairs(rp_formspec.registered_invpages) do
           if def.is_startpage and def.is_startpage(pname) then
-             rp_formspec.set_invpage(player, invpagename)
+             rp_formspec.set_current_invpage(player, invpagename)
           end
       end
       -- Fallback invpage
-      if not rp_formspec.get_invpage(player) then
-         rp_formspec.set_invpage(player, "rp_formspec:inventory")
+      if not rp_formspec.get_current_invpage(player) then
+         rp_formspec.set_current_invpage(player, "rp_formspec:inventory")
       end
 end)
 
diff --git a/mods/rp_player_skins/init.lua b/mods/rp_player_skins/init.lua
index 77bb793..b43b450 100644
--- a/mods/rp_player_skins/init.lua
+++ b/mods/rp_player_skins/init.lua
@@ -241,7 +241,7 @@ minetest.register_on_joinplayer(on_joinplayer)
 minetest.register_on_leaveplayer(on_leaveplayer)
 
 local function get_formspec(playername)
-	local form = rp_formspec.get_page("rp_player_skins:player_skins")
+	local form = rp_formspec.get_page("rp_player_skins:player_skins", true)
 	form = form .. "model[0.2,0.2;4.6,9.2;player_skins_skin_select_model;character.b3d;"..player_skins.skins[playername]..";0,180;false;false;0,0]"
 	return form
 end