Ok, when I say locked, my $InvForm refuses to respond to events, and when it loses the focus, refuses to regain focus, despite several experiments with OnLostFocus = {procedure to resest focus} or {procedure to have windows switch app focus} or so on and so forth. The full code is pretty hefty, but here is the loop:

While $InvForm.Visible
? "Looping"
$=Execute($InvForm.DoEvents)
Loop

When run with the console, I get one line of "looping", then kix32.exe must be killed. I can't end the process.

exit 1