>I admit I also thought it unlikely. Sounds as if Joel may have been on the right track tho'. If double clicking can close the *entire* app then obviously it also closes the dialogs parent window - maybe just that, in *some* scenarios, it also goes on to close the main window
>
>I tried my level best to reproduce the behavior and was not able to.

Surely if you can get the app to exit completely by double-clicking then a few judiciously placed Debug.Writeline() or breaking and examing the stack trace should reveal what is going on ?