Trapped in OPO Debugger

I must be missing something very simple, but often when running a form in design mode, the form vanishes (usually after an error of some kind, or if a method calls HideWindow). I am then unable to get back to design mode. If I click on the stop execution icon, the debug window closes, but I'm in limbo. Under Windows, the windows are there, but greyed out. I've searched the manuals and on-line help, but this must be something so basic everyone is expected to know it (or I am just missing it) because I can't find anything about this. Help!

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Randy Gellens                               "I speak for myself alone"                             Randy_at_Pensive.Org