Board Thread:The Drax Cave/@comment-188432-20130206223313/@comment-188432-20130207150050

Wikia have responded that the disappearance of hidden categories was unintended and that it'll be fixed soon. There is a temporary workaround, but it will remove the "add category" button from the category box — meaning that you'll be forced to edit a page to add a category. If you'd like to avail yourself of this workaround, go to Special:Preferences/Editing and click "disable category module". Hidden cats will then show.