In the edit area of your knowledge base for comments, categories and articles at the bottom of the page you will see hide with the choice of yes or no in the drop down selector. If the selection is no the item appears in your knowledge base, if yes the item is hidden and will not appear in your knowledge base. The purpose of this is to allow you to remove items from the visitor view without completely removing them from your database. If an item is suspended or waiting validation it is hidden. Once it is corrected or validated it is changed to no and the item will then become visible in the knowledge base again.

In your admin panel's "search / edit" page you will see links to show all the hidden items for comments, categories and articles. This will allow you to view items hidden in your knowledge base so that you can edit and make the necessary changes to these items.