Version 2.5.1 - http://otclient.net/showthread.php?tid=249

modules/game_outfit/outfit.lua

@@ -106,7 +106,7 @@ function setupSelector(widget, id, outfit, list)
     widget.label:setText(list[pos][2])   
     updateOutfit()    
   end  
-  return w
+  return widget
 end
 
 function create(currentOutfit, outfitList, mountList, wingList, auraList, shaderList)
@@ -219,10 +219,12 @@ end
 function accept()
   local outfit = outfitWindow.type.creature:getOutfit()
   for i, child in pairs(outfitWindow.extensions:getChildren()) do
-    if child:getId() == "shader" then
-      outfit[child:getId()] = child.creature:getOutfit().shader
-    else
-      outfit[child:getId()] = child.creature:getOutfit().type
+    if child.creature:getCreature() then
+      if child:getId() == "shader" then
+        outfit[child:getId()] = child.creature:getOutfit().shader
+      else
+        outfit[child:getId()] = child.creature:getOutfit().type
+      end
     end
   end
   g_game.changeOutfit(outfit)

modules/game_outfit/outfitwindow.otui

@@ -157,13 +157,6 @@ MainWindow
       fit-children: true
       spacing: 3
 
-  HorizontalSeparator
-    anchors.left: parent.left
-    anchors.right: parent.right
-    anchors.bottom: next.top
-    margin-bottom: 5
-    margin-top: 5
-
   Button
     id: outfitOkButton
     !text: tr('Ok')