>>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.
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>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)?
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>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).

I think what we have here is a failure to communicate.:-)

First, VFP receives a WM_HELP message whenever the user presses the F1 key. This is standard behavior for all windows. What it does then is the point where I believe we're confusing the issue. What VFP does next is to see if the HH help engine is running (via a query message). If so it then passes more messages to the window telling it to activate itself.

The question isn't really, "Does VFP receive a WM_HELP message?" The answer is undoubted yes because VFP can do nothing about the standard messages that windows sends. What it can do something about is how it processes. For example, if you issue ON KEYLABEL F1 from the command window, then press F1, help doesn't come up because you've effectively told VFP not to process the message.

In the case of the MessageboxEx() dialog, it's getting back a WM_HELP message probably when it thinks it shouldn't and ignores it or doesn't know what to do with it.