>>No, i don't use LASTKEY() or other functions that test the keyboard input.
>>This thing has driven me nuts. The form behave incorrectly when I ran
>>it, but I can't use the tracer to trap the error because the form
>>behave correctly when run through the tracer.
>
>Try the old fashion way of using Wait Windows to determine where the problem is located. Are U using the KeyPress event also?

Paul, Steve, Yung, thanks for your answers.
I changed the order of my code and after that it worked fine.