Understood. I actually tried to modify the gate number using AFX. But after that, GSX doesn't work, did I do something wrong?
If you rename the AFCAD, GSX will not recognize the airport as being customized anymore so, GSX will still work, but in default mode. If you create an AFCAD conflict, instead, it's likely you'll have other issues too, including disappearing objects, etc.
if you change some parking numbers, it's also possible GSX will not see part of the gates.