If you customize your UI a bit and have installed the "3dsMax 2011 Subscription Advantage Pack" or the NVidia PhysX utility for 3dsMax, you should notice that it adds menus to the Customize Dialog every time you run 3dsMax. In a month or so, you will probably have to scroll over a thousand duplicates in the Customize Menus Dialog.
I had a quick look in the PhysX MaxScript files, but I don't want to mess with it. Instead, I made this simple script, that will remove all PhysX menus when 3dsMax shuts down. Don't worry, they'll be added again next time you start.