Hi Robin:
In addition to what Tore suggested, there is also another approach you could try. In my experience, Fox has a fundamental issue with controls setting focus back to themselves. Tore's suggestion in using the valid to return False stops the control from losing focus, a subtle difference. If you dont want to use the valid, you could create an off-screen control (top -100, left -100). If your user wants to Retry, set focus to the off-screen control that can in turn bounce focus back to the estimate number control. Obviously, this type of technique is only something that should be considered for an important control. You dont want to be creating lots of off-screen controls just to re-route focus <s>.
HTH
-=Gary