Now .. I’m one of those types of people who, sometimes, in their haste, publishes a page without filling all of the fields—including the category field.

When this happens, of course, the page seeems not to appear in the navigation!

Enter “DC Required Category Extension” .. an extension which allows you to define which weblogs must have at least one category assigned when submitting new entries

http://www.designchuchi.ch/index.php/blog/comments/required-category-extension/