I have an MDI application. One of the forms in the app has a subform that is set as topmost. Everything works until another application is started when this subform is active. In that case, the subform continues to hover above everything! Not desirable behavior... Is there any simple key someone can give me to let the app know that it is no longer the top most application and cosequently hide this bothersome subform. Thanks.

Things tried already-

The deactivate event of the MDI form - fires too often
The deactivate event of the parentform to the subform - does NOT fire when a new application opens over it. The MDI form does fire but how can it be differentiated.

Thanks for any help...