>>Can you post the whole command you're using. ON KEY RIGHTMOUSE gives an error if try to run it.
>
>ON KEY LABEL RIGHTMOUSE DO START.MPR
>
>That menu allows me to switch between various projects for faster maintenance. So, from the menu, I select an item, a modify project is invoked and I'm in that specific project for maintenance.

My guess would be that disabled menu item has something to do with START.MPR. To verify that, start fresh copy of VFP and try to modify some class. Make sure that you don't use righ-click before that. If property Window menu is enabled than it's start.mpr.