Category Design Tab disappeared!

Question

I actually have no idea where to begin troubleshooting this, since I haven't really touched anything with Magento's backend. The only sin I've committed is by editing the database directly, but only as it relates to attributes. I use Magmi to import products, and have been for a while, and it was after a recent import that I noticed the Category Design tabs were missing. But I am constantly tinkering with this installation, preparing it for launch so it could have been anything.

Disabling modules has no effect. Any ideas where I can start troubleshooting/fixing this, other than reinstalling Magento?

The only tabs I have when editing a category are "General Information" and "Category Products"

Answer 1

The missing tabs are declared as attribute groups in the database table eav_attribute_group. This query

SELECT attribute_group_name FROM eav_attribute_group WHERE attribute_set_id = (SELECT default_attribute_set_id FROM eav_entity_type WHERE entity_type_code = 'catalog_category');

should give you

+----------------------+
| attribute_group_name |
+----------------------+
| Custom Design        |
| Display Settings     |
| General Information  |
+----------------------+

Somehwere in there you must have damaged the database integrity.