Sounds like you should be using a drop down list instead of a pop up menu. You can set a field validation option to limit user input to just the values of the value list.
Thanks for taking that up Phil. It was actually the delete or backspace key I was after...sigh...
As an aside, I have become averse to drop downs, although they have clear pluses, because I don't like them in ios the way they pop up the keyboard. I d rather go from pop up to op up with set values and no keyboard.
Yes, but you are posting to the FileMaker Pro forum. If you want to discuss issues with FM GO, the FM GO forum (See tab at top of screen) would seem the better place to discuss that. Otherwise, people such as myself will assume that you are discussing FM Pro--where the drop down list can be the better layout design option.