Every time I open the GSX menu it appears only a few options. In large airports, after landing, I can not select any gate, it only appears the runways.
Already discussed and answered here, in the thread named "GSX small window"
http://www.fsdreamteam.com/forum/index.php/topic,14161.0.htmlOf course, it doesn't have anything to do with GSX: it's a known P3D problem with the new Scaleform menu, and it has been reported many times on our forum, even if doesn't have anything to do with GSX, of course. It will affect any 3rd party application with a menu, like FsPassengers, Sode, etc.
Just resize the menu manually.
Another question is about the audio, it is not working
That's because you haven't selected the correct audio device in the GSX Settings. Usually happens if you switch between different devices (for example, usb headphones and speakers).
Verify the correct audio device is selected, then Restart Couatl.