Determining When an Application Goes into the Background

I am developing a graphics application embedded in MFC. I need to know when the application is in the background to stop the simulation loop otherwise it eats up all the CPU cycles. I have tried using OnKillFocus but that doesn't appear to be the right windows message. Does anyone know how to determine when my application has gone into the background? Please help. Thanks.

Chad Goolbis
[email protected]

I believe U need to override WM_WINDOWPOSCHANGED.

Good luck and hope U can help others, too. :)

Walter

OnActivate() ??

sally