If you see the GSX menu, it means it's *working*. If you see the gate selection menu, it means that you are not parked on a parking position, or the AFCAD isn't recognized it.
Check you don't have a problem with your FSX scenery cache, this might be fixed by removing the following folder:
C:\ProgramData\Microsoft\FSX\SceneryCache
and let FSX and GSX rebuild their cache.