>>>Is there a way to trap the a WM_USER message sent to the main foxpro window?
...
>>There's no way to "trap" (as you would with a keystroke), but setting a timer up to call the PeekMessage API function will allow you to simulate this behavior.
>>
>
>What about hooking the system messages with SetWindowsHookEx()?
>

A curous side note about your question:
On page 29 of the current issue of VBPJ, January 1998, is the following statement:
"Subclassing a window or a control simply means intercepting all the messages that
are sent to it. Subclassing has several variants: ...hooking...intercepting...trapping...
and processing trapped msgs......"

And all along we poor VFP programmers thought that sublcassing really meant
creating a decentant ojbect containing all the properties and methods and
objects of the ancestor (parent). All we really had to do was cut and paste from
our source form and then add message interception.