I've noticed something in your Parent Form's Load event:

Code:
Private Sub Form_Load()
    . . .
'Show first form
  frmabFront.Show vbModal, Me    '<-- Is this intentional?
End Sub
You do know that until frmabFront is hidden or unloaded, your Parent Form won't show itself?

I can't see anything in your posted code that might be causing F1 to be ignored. There's probably something else in your code that's the real culprit.