jdmenu help in IE6

I'm having an issue with jdmenu in IE6. You can view my problem here:

http://www.jeffrobertswebdesign.com/monroe/

The main menu drops down just fine, but when a menu item that contains a sub menu is hovered over, the height of that menu item increases. How can I prevent this from happening? It does not happen in any browser I've tested it in other than IE6.

Thanks for the help.