Simon,

It sounds like you are on the right track to finally figuring out what's causing the problem.

I always use the FoxPro frame for the debugger windows, I just find that the most convenient way to do it.

>I had an opportunity to test two forms with 10 controls on each form as you suggested and everything worked correctly. So I proceeded to create a toolbar with two graphical check boxes that simply issued loFormA.Show or loFormB.Show when clicked. I clicked the check boxes may times and I never experienced a problem. Then I ran the application where I had the problem the day before. No matter how many times I clicked the toolbar buttons I could not make the forms display incorrectly. Yet the previous day I would have an incorrectly displayed form after two or three clicks on the toolbar buttons.
>
>I will try some more testing by gradually adding functionality to my test program until it matches my app and see what happens.
>
>I also have experienced the debugger window not showing on top of the application being debugged but stuck behind VFP. The only way to view it is minimze VFP.