window closable with escape and fixed a bug with foror's item class

core.lua

@@ -22,6 +22,7 @@ Aux = {
 function Aux_OnLoad()
 	Aux.log('Aux v'..AuxVersion..' loaded.')
 	Aux.loaded = true
+    tinsert(UISpecialFrames, 'AuxFrame')
 end
 
 function Aux_OnEvent()

item_search_frame.lua

@@ -517,7 +517,7 @@ function public.start_search()
     local item_info = Aux.info.item(item_id)
 
     local class_index = Aux.item_class_index(item_info.class)
-    local subclass_index = Aux.item_subclass_index(class_index, item_info.subclass)
+    local subclass_index = class_index and Aux.item_subclass_index(class_index, item_info.subclass)
 
 	search_query = {
 		name = item_info.name,