diff --git a/api.lua b/api.lua
index 64efe0b..1609217 100644
--- a/api.lua
+++ b/api.lua
@@ -151,7 +151,7 @@ minetest.after(0.01, function()
 	-- Step 2: Find all matching items for the given spec (groups)
 	local function get_matching_spec_items(specname)
 		if specname:sub(1,6) ~= "group:" then
-			return { specname }
+			return { [specname] = true }
 		end
 
 		local accepted = {}
@@ -177,6 +177,7 @@ minetest.after(0.01, function()
 	end
 
 	for _, recipes in pairs(ui.crafts_for.recipe) do
+		-- List of crafts that return this item string (variable "_")
 		for _, recipe in ipairs(recipes) do
 			local ingredient_items = {}
 			for _, spec in pairs(recipe.items) do
diff --git a/callbacks.lua b/callbacks.lua
index e92175d..fa6d03a 100644
--- a/callbacks.lua
+++ b/callbacks.lua
@@ -19,14 +19,12 @@ minetest.register_on_joinplayer(function(player)
 		unified_inventory.items_list
 	unified_inventory.activefilter[player_name] = ""
 	unified_inventory.active_search_direction[player_name] = "nochange"
-	unified_inventory.apply_filter(player, "", "nochange")
 	unified_inventory.current_searchbox[player_name] = ""
 	unified_inventory.current_category[player_name] = "all"
 	unified_inventory.current_category_scroll[player_name] = 0
 	unified_inventory.alternate[player_name] = 1
 	unified_inventory.current_item[player_name] = nil
 	unified_inventory.current_craft_direction[player_name] = "recipe"
-	unified_inventory.set_inventory_formspec(player, unified_inventory.default)
 
 	-- Refill slot
 	local refill = minetest.create_detached_inventory(player_name.."refill", {
@@ -48,6 +46,14 @@ minetest.register_on_joinplayer(function(player)
 	refill:set_size("main", 1)
 end)
 
+minetest.register_on_mods_loaded(function()
+       minetest.register_on_joinplayer(function(player)
+               -- After everything is initialized, set up the formspec
+               ui.apply_filter(player, "", "nochange")
+               ui.set_inventory_formspec(player, unified_inventory.default)
+       end)
+end)
+
 local function apply_new_filter(player, search_text, new_dir)
 	local player_name = player:get_player_name()
 
diff --git a/init.lua b/init.lua
index 12a14ed..8bb2360 100644
--- a/init.lua
+++ b/init.lua
@@ -50,7 +50,7 @@ unified_inventory = {
 	trash_enabled = (minetest.settings:get_bool("unified_inventory_trash") ~= false),
 	imgscale = 1.25,
 	list_img_offset = 0.13,
-	standard_background = "background9[0,0;1,1;ui_formbg_9_sliced.png;true;16]",
+	standard_background = "bgcolor[#0000]background9[0,0;1,1;ui_formbg_9_sliced.png;true;16]",
 
 	version = 4
 }
diff --git a/internal.lua b/internal.lua
index b264d22..938ca19 100644
--- a/internal.lua
+++ b/internal.lua
@@ -115,9 +115,9 @@ local function formspec_add_categories(player, formspec, ui_peruser)
 		ui_peruser.form_header_y - (ui_peruser.is_lite_mode and 0 or 0.2)
 	}
 
-	formspec[n] = string.format("background9[%f,%f;%f,%f;%s;false;3]",
-		ui_peruser.page_x-0.1, categories_scroll_pos[2],
-		(ui_peruser.btn_spc * ui_peruser.pagecols) + 0.13, 1.4 + (ui_peruser.is_lite_mode and 0 or 0.2),
+	formspec[n] = string.format("background9[%f,%f;%f,%f;%s;false;16]",
+		ui_peruser.page_x-0.15, categories_scroll_pos[2],
+		(ui_peruser.btn_spc * ui_peruser.pagecols) + 0.2, 1.4 + (ui_peruser.is_lite_mode and 0 or 0.2),
 		"ui_smallbg_9_sliced.png")
 	n = n + 1
 
@@ -256,8 +256,14 @@ local function formspec_add_item_browser(player, formspec, ui_peruser)
 					ui_peruser.btn_size, ui_peruser.btn_size,
 					name, button_name
 				)
+				local tooltip = item.description
+				if item.mod_origin then
+					-- "mod_origin" may not be specified for items that were
+					-- registered in a callback (during or before ServerEnv init)
+					tooltip = tooltip .. " [" .. item.mod_origin .. "]"
+				end
 				formspec[n + 1] = ("tooltip[%s;%s]"):format(
-					button_name, minetest.formspec_escape(item.description)
+					button_name, minetest.formspec_escape(tooltip)
 				)
 				n = n + 2
 				list_index = list_index + 1
diff --git a/screenshot.png b/screenshot.png
index 972cbb4..bf9e6be 100644
Binary files a/screenshot.png and b/screenshot.png differ
diff --git a/textures/ui_formbg_9_sliced.png b/textures/ui_formbg_9_sliced.png
index 0b8463c..817ced5 100644
Binary files a/textures/ui_formbg_9_sliced.png and b/textures/ui_formbg_9_sliced.png differ
diff --git a/textures/ui_smallbg_9_sliced.png b/textures/ui_smallbg_9_sliced.png
index 865e0c9..916b146 100644
Binary files a/textures/ui_smallbg_9_sliced.png and b/textures/ui_smallbg_9_sliced.png differ