diff --git a/api.lua b/api.lua
index 1609217..e4b67fa 100644
--- a/api.lua
+++ b/api.lua
@@ -2,40 +2,49 @@ local S = minetest.get_translator("unified_inventory")
 local F = minetest.formspec_escape
 local ui = unified_inventory
 
+local function is_recipe_craftable(recipe)
+	-- Ensure the ingedients exist
+	for _, itemname in pairs(recipe.items) do
+		local groups = string.find(itemname, "group:")
+		if groups then
+			if not ui.get_group_item(string.sub(groups, 8)).item then
+				return false
+			end
+		else
+			-- Possibly an item
+			if not minetest.registered_items[itemname]
+					or minetest.get_item_group(itemname, "not_in_craft_guide") ~= 0 then
+				return false
+			end
+		end
+	end
+	return true
+end
+
 -- Create detached creative inventory after loading all mods
 minetest.after(0.01, function()
 	local rev_aliases = {}
-	for source, target in pairs(minetest.registered_aliases) do
-		if not rev_aliases[target] then rev_aliases[target] = {} end
-		table.insert(rev_aliases[target], source)
+	for original, newname in pairs(minetest.registered_aliases) do
+		if not rev_aliases[newname] then
+			rev_aliases[newname] = {}
+		end
+		table.insert(rev_aliases[newname], original)
 	end
+
+	-- Filtered item list
 	ui.items_list = {}
 	for name, def in pairs(minetest.registered_items) do
-		if (not def.groups.not_in_creative_inventory or
-		   def.groups.not_in_creative_inventory == 0) and
-		   def.description and def.description ~= "" then
+		if ui.is_itemdef_listable(def) then
 			table.insert(ui.items_list, name)
+
+			-- Alias processing: Find recipes that belong to the current item name
 			local all_names = rev_aliases[name] or {}
 			table.insert(all_names, name)
-			for _, player_name in ipairs(all_names) do
-				local recipes = minetest.get_all_craft_recipes(player_name)
-				if recipes then
-					for _, recipe in ipairs(recipes) do
-
-						local unknowns
-
-						for _,chk in pairs(recipe.items) do
-							local groupchk = string.find(chk, "group:")
-							if (not groupchk and not minetest.registered_items[chk])
-							  or (groupchk and not ui.get_group_item(string.gsub(chk, "group:", "")).item)
-							  or minetest.get_item_group(chk, "not_in_craft_guide") ~= 0 then
-								unknowns = true
-							end
-						end
-
-						if not unknowns then
-							ui.register_craft(recipe)
-						end
+			for _, itemname in ipairs(all_names) do
+				local recipes = minetest.get_all_craft_recipes(itemname)
+				for _, recipe in ipairs(recipes or {}) do
+					if is_recipe_craftable(recipe) then
+						ui.register_craft(recipe)
 					end
 				end
 			end
@@ -44,6 +53,8 @@ minetest.after(0.01, function()
 	table.sort(ui.items_list)
 	ui.items_list_size = #ui.items_list
 	print("Unified Inventory. Inventory size: "..ui.items_list_size)
+
+	-- Analyse dropped items -> custom "digging" recipes
 	for _, name in ipairs(ui.items_list) do
 		local def = minetest.registered_items[name]
 		-- Simple drops
@@ -201,8 +212,8 @@ minetest.after(0.01, function()
 	end
 end)
 
+---------------- Home API ----------------
 
--- load_home
 local function load_home()
 	local input = io.open(ui.home_filename, "r")
 	if not input then
@@ -219,6 +230,7 @@ local function load_home()
 	end
 	io.close(input)
 end
+
 load_home()
 
 function ui.set_home(player, pos)
@@ -247,7 +259,8 @@ function ui.go_home(player)
 	return false
 end
 
--- register_craft
+---------------- Crafting API ----------------
+
 function ui.register_craft(options)
 	if not options.output then
 		return
@@ -270,14 +283,12 @@ function ui.register_craft(options)
 	end
 end
 
-
 local craft_type_defaults = {
 	width = 3,
 	height = 3,
 	uses_crafting_grid = false,
 }
 
-
 function ui.craft_type_defaults(name, options)
 	if not options.description then
 		options.description = name
@@ -288,8 +299,7 @@ end
 
 
 function ui.register_craft_type(name, options)
-	ui.registered_craft_types[name] =
-			ui.craft_type_defaults(name, options)
+	ui.registered_craft_types[name] = ui.craft_type_defaults(name, options)
 end
 
 
@@ -346,6 +356,8 @@ ui.register_craft_type("digging_chance", {
 	height = 1,
 })
 
+---------------- GUI registrations ----------------
+
 function ui.register_page(name, def)
 	ui.pages[name] = def
 end
@@ -361,6 +373,8 @@ function ui.register_button(name, def)
 	table.insert(ui.buttons, def)
 end
 
+---------------- Callback registrations ----------------
+
 function ui.register_on_initialized(callback)
 	if type(callback) ~= "function" then
 		error(("Initialized callback must be a function, %s given."):format(type(callback)))
@@ -375,6 +389,8 @@ function ui.register_on_craft_registered(callback)
 	table.insert(ui.craft_registered_callbacks, callback)
 end
 
+---------------- List getters ----------------
+
 function ui.get_recipe_list(output)
 	return ui.crafts_for.recipe[output]
 end
@@ -387,11 +403,15 @@ function ui.get_registered_outputs()
 	return outputs
 end
 
+---------------- Player utilities ----------------
+
 function ui.is_creative(playername)
 	return minetest.check_player_privs(playername, {creative=true})
 		or minetest.settings:get_bool("creative_mode")
 end
 
+---------------- Formspec helpers ----------------
+
 function ui.single_slot(xpos, ypos, bright)
 	return string.format("background9[%f,%f;%f,%f;ui_single_slot%s.png;false;16]",
 	xpos, ypos, ui.imgscale, ui.imgscale, (bright and "_bright" or "") )
diff --git a/category.lua b/category.lua
index d0fee5e..46b3e02 100644
--- a/category.lua
+++ b/category.lua
@@ -96,6 +96,9 @@ function unified_inventory.register_category(category_name, config)
 	end
 	update_category_list()
 end
+
+-- TODO: Mark these for removal. They are pretty much useless
+
 function unified_inventory.set_category_symbol(category_name, symbol)
 	ensure_category_exists(category_name)
 	unified_inventory.registered_categories[category_name].symbol = symbol
diff --git a/internal.lua b/internal.lua
index 938ca19..3fbf5b7 100644
--- a/internal.lua
+++ b/internal.lua
@@ -329,7 +329,7 @@ function ui.set_inventory_formspec(player, page)
 	end
 end
 
-local function valid_def(def)
+function ui.is_itemdef_listable(def)
 	return (not def.groups.not_in_creative_inventory
 			or def.groups.not_in_creative_inventory == 0)
 		and def.description
@@ -342,9 +342,11 @@ function ui.apply_filter(player, filter, search_dir)
 		return false
 	end
 	local player_name = player:get_player_name()
+
 	local lfilter = string.lower(filter)
 	local ffilter
 	if lfilter:sub(1, 6) == "group:" then
+		-- Group filter: all groups of the item must match
 		local groups = lfilter:sub(7):split(",")
 		ffilter = function(name, def)
 			for _, group in ipairs(groups) do
@@ -356,6 +358,7 @@ function ui.apply_filter(player, filter, search_dir)
 			return true
 		end
 	else
+		-- Name filter: fuzzy match item names and descriptions 
 		local player_info = minetest.get_player_information(player_name)
 		local lang = player_info and player_info.lang_code or ""
 
@@ -368,35 +371,41 @@ function ui.apply_filter(player, filter, search_dir)
 				or llocaldesc and string.find(llocaldesc, lfilter, 1, true)
 		end
 	end
-	ui.filtered_items_list[player_name]={}
+
+	local is_itemdef_listable = ui.is_itemdef_listable
+	local filtered_items = {}
+
 	local category = ui.current_category[player_name] or 'all'
 	if category == 'all' then
 		for name, def in pairs(minetest.registered_items) do
-			if valid_def(def)
+			if is_itemdef_listable(def)
 			and ffilter(name, def) then
-				table.insert(ui.filtered_items_list[player_name], name)
+				table.insert(filtered_items, name)
 			end
 		end
 	elseif category == 'uncategorized' then
 		for name, def in pairs(minetest.registered_items) do
-			if (not ui.find_category(name))
-			and valid_def(def)
+			if is_itemdef_listable(def)
+			and not ui.find_category(name)
 			and ffilter(name, def) then
-				table.insert(ui.filtered_items_list[player_name], name)
+				table.insert(filtered_items, name)
 			end
 		end
 	else
-		for name,exists in pairs(ui.registered_category_items[category]) do
+		-- Any other category is selected
+		for name, exists in pairs(ui.registered_category_items[category]) do
 			local def = minetest.registered_items[name]
 			if exists and def
-			and valid_def(def)
+			and is_itemdef_listable(def)
 			and ffilter(name, def) then
-				table.insert(ui.filtered_items_list[player_name], name)
+				table.insert(filtered_items, name)
 			end
 		end
 	end
-	table.sort(ui.filtered_items_list[player_name])
-	ui.filtered_items_list_size[player_name] = #ui.filtered_items_list[player_name]
+	table.sort(filtered_items)
+
+	ui.filtered_items_list_size[player_name] = #filtered_items
+	ui.filtered_items_list[player_name] = filtered_items
 	ui.current_index[player_name] = 1
 	ui.activefilter[player_name] = filter
 	ui.active_search_direction[player_name] = search_dir