First, the key command didn't work, I had to pull it from the Addon Manager in the FSX menu bar
If calling GSX from the menu works, but calling it with the hotkey doesn't, it means GSX clearly works, and another addon is conflicting with its key so, you must either reassign the default hotkey in GSX, or in the other conflicting addon, so they won't conflict anymore.
Then , I got a list of commands to either place me at a hold or activate or deactivate the deicers, nothing at all about boarding, fueling, or pushback. I was at a proper gate, I changed to another gate, same thing. I tried a different airport, KLAS, and I get a menu to open the Atlantic hangar, the Pacific hanger etc.
What you are looking at, is the YouControl menu, which is a menu that comes out on our sceneries to control their options. However, the first entry of this menu should be the option to call GSX. If the scenery doesn't have an YouControl menu, CTRL+F12 will call GSX.
If you don't have the option to call GSX, it simply means you haven't installed GSX. If you have the QW757, you must install it first, then install all the FSDT/Flightbeam stuff using ONLY the CURRENT installers. Their installation order doesn't matter, as long you install the QW757 before anything else.
If GSX is installed, you should see its own menu, and it will be assigned to its own hotkey, which by default is CTRL+Shift+F12, which will always call GSX directly, regardless if the scenery has a YouControl menu or not.
But again, if some other addon is conflicting (check Ezdok camera, for example, since it steals F12 entirely), you won't be able to use the Hotkeys unless you fix the conflict, so the programs will only start from the Addons menu. Assuming, of course, you have installed GSX, because if you don't, there wouldn't be a GSX menu to begin with.