>WM_HELP, is sent if ON('KEY', 'F1') = 'HELP'. If it's own error dialogs, then VFP wouldn't necessarily be using WM_HELP. I can't find what message VFP sends to activate it's help, but pressing F1 does generate a WM_HELP message that VFP processes if no dialog is present.

I couldn't get VFP to do this. Were you looking at the main window or one of VFP's child windows (or one of its extraneous windows)?

When you say no dialogs present, do you mean within VFP itself? If so, that didn't work for me (VFP6 SP4, NT4 SP6). I even closed all toolbars and the Command window (even though that still existed, just no WM_VISIBLE attribute).