GSX reads the AFCAD, but it won't care if the runway is closed or not, because you might want to use the menu to just "warp" there.
Of course, if you are currently ON a runway start, you won't see in the list the runway start position YOU are now located, because it wouldn't make much sense to have you re-warp when you are already there, or ask for a follow me to where you are currently standing.