PopUp display only

I need to have a screen popup based on field entry that will show the user their choices for that field. The thing is, I need the cursor to remain in that field, on the parent window, so the user can enter a selection number from the display. I don't want the focus to shift to the new screen, which seems to happen no matter what I try in the way of grab commands. Is there any way to do this? thanks Madeleine D.