Comment and clean up the code. Readd flex/width when moving the item back to the palette to ensure proper spacing.

git-svn-id: svn://10.0.0.236/trunk@126612 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/browser/base/content/customizeToolbar.js

@@ -251,7 +251,9 @@ var paletteDNDObserver = {
       }
       toolbarItem = toolbarItem.nextSibling;
     }
-    
+    if (!item)
+      return;
+
     // We're going back in the palette now, so we have to readd the flex
     // and width which we removed when moving the item to the toolbar.
     // (These attributes help space the items properly in the palette.)