>Is there a foolproof way of determining if a window (given either it's hWnd or WHandle) is a VFP code editor window? I've been using _EdGetEnv (and checking for a return value of 0) but it seems to fail under various circumstances (that is, _EdGetEnv seems to throw an exception). I thought about using the Win32 GetClassName() call but I don't see anything that differentiates something like the Property window from the editor Window (it seems some windows DO return a slightly different result, though).

I guess that _EdGetEnv throws exeption on noe-editor windows, right?
Why don't you wrap calls to _EdGetEnv in TRY...ENDTRY?