gcw1:
I haven't tried doing any sophisticated tricks in fox before visual in some time, and I don't remember if there was a bug in the list control, but if you truely can't get it to work, maybe try using an invisible push button that you set focus to and then performs the screen hide, do new screen, screen show routine. The pushbutton should only allow itself to be selected if some variable is set to a known value or someother such trickery.
Also, it may be simpler to just have the other screen active already and then pop it to the top of screen stack when needed. (takes a lot less work also)
Good luck,
Darrell