>Is there a reliable way to determine the actual order in which forms are opened or used?

If you need to know, then I suggest creating a Form manager for your app.

>Perhaps automatically close minimized forms in a FIFO order once the limit is reached.

If you go this route, I'd make sure that you inform the user about whats going on and let them abort.

>Can anyone confirm how _SCREEN.FORMS() collection orders forms.

I think you're right. When a form is activated, it is moved to teh top and pushes everything else down.