I'll confirm that, if you have any problem with keys not recognized, it doesn't have anything to do with GSX. We don't even try to read or interact with the keyboard. We just ask the sim to be notified when an EVENT happens.
The actual key doesn't really matter, we just wait for the desired event to happen. In case of the two Editor (the Airplane configuration editor and the Parking editor), we wait for the various SLEW Events so, whatever key you have assigned to it in the Controls Setting, it will work. And, if you haven't assigned anything, which not the default, no event will reach GSX which won't work.
That's why I said to first try to RESET the FSX Controls page to the default settings, to be sure you haven't inadvertedly un-set the keys assigned to the Slew events.
Of course, the only other possible reason for this to happening (unless you have some kind of problem with the NumLock key), is that ANOTHER addon is trying to use the same Events and, if that has been loaded before GSX, it will steal the keys from it.
But regardless of the reason, you can be sure of one thing, that's it's nothing that is related to GSX, it's happening entirely outside it.
