You screenshots clearly indicate that none of the problems you are having have anything to do with GSX.
- The 1st screen shows default jetways.
- Those in the 2nd screen are NOT the GSX L2 replacement jetways! ( GSX L2 jetways looks way better ), those are SODE jetways that have been added or are coming from the remnants of a 3rd party scenery that came with ITS OWN SODE XML jetways, and you are probably disabled or removed, leaving the SODE files in place.
You are probably assuming "they came with GSX", only because GSX installed SODE.
What really happened, most likely, is that you had a 3rd party scenery that came with SODE and installed its own SODE jetways, then you removed it, so you are now with the default scenery, but the SODE XML file for that airport is still there, in the %PROGRAMDATA%\12bpilot\SODE\XML folder so, as soon as you reinstalled GSX, which reinstalled SODE, those jetways became active again but, since the scenery they were originally made for is not there, they are not connecting to the terminal.
- GSX, of course, sees you already have SODE XML jetways, so it has disabled any editing, which is entirely normal, since if a scenery already has SODE jetways on its own, GSX doesn't try to replace them.
If you remove the XML for that airport located here:
%PROGRAMDATA%\12bpilot\SODE\XML
You'll finally see the much better looking GSX L2 jetways, fully editable.