I'm using a theme which, instead of displaying child pages as subpages in the main navigation, creates a separate submenu on the parent page. Here's a page where it's working: http://www.jaydixit.com/articles/
But when I upload a photo or a PDF to a page, it evidently thinks the file is a child page, for it creates a submenu with no items in it:
How do I upload a photo, PDF, or item to a page without creating a null submenu? Or rather, how do I get rid of the null submenu on pages with items uploaded?