Junction table with combo box problem

Hi,

I cannot figure out how to create a sub-form with a combo box that works.  My database has a Menu Items table and a Menu Category table.  I've created a junction table and related these other tables to it appropriately.  I have a form called Menu Item Entry that allows the user to edit a particular menu item and then in a sub-form with a combo box, assign all the categories that the menu item can belong to. I can't get this to work correctly.  Any help would be greatly appreciated!

Thanks!
Menu-Database-Sample.accdb