Microsoft Visual Basic for Applications window keeps popping up

I am am not sure if this is the place for this question, but I am not sure where else to go with this.

I have a MS Access VBA database/application which has been running pretty good. However, today, for no real apparent reason the Microsoft Visual Basic for Applications window keeps popping up. This is the application window where you manage your VBA code for MS Access and possibly other MS Office programs, except that there are no menus, just the code frame and two additional side frames one of which is the project explorer. There are no error messages, the program is running fine. I can't think of any reason why it is behaving this way. Has anyone seen this before?

Thanks