I am experiencing a problem with the menu bar on the application I am developing.

This application's menu structure is defined completely through the database. The menu bar and sub-menus are created with the Windows API.

My problem is that sometimes at random, one or more of the menus will not drop down when I run the program in Vista or Windows 7. I don't recall this problem ever happening when I had XP for my development environment.

I have been looking over the code to build the menu bar, and I have noticed that the API call to CreateMenu does return a negative value for the sub-menus that do not show up on any given run.

Any thoughts on why CreateMenu will sometimes return a negative?