Magento Notes - Fix for product category becoming blank
After upgrading from version 1.1.6 to 1.2.1, there has been many issus with files not being updated properly. The new problem deals with when you are editing a product (Catalog -> Manage Products) and you go to the “Categories” link at the left pane, you may see a screen with title “Product Categories” and nothing else. Refer to pix.
Another system to this problem is that when you are in the Category Manager and you attempt to expand a parent category, you will just get the spinning wheel..and it would run forever.
the fix for both issues is to replace the “head.phtml” inside: magento/app/design/adminhtml/default/default/template/page
The fix was found here, but under a different topic: http://www.magentocommerce.com/boards/viewthread/27032/P75/#t101188
