Jack,

Is this a VFP application you're trying to activate? I have had some problems with some other applications (Excel, today, in fact) not painting properly after being told to maximize from VFP via an automation server. The only solution I've found (so far) was to re-start VFP.

SWAG -- In you're code, try calling SetForegroundWindow() (I think that was the function) before the ShowWindow() calls