Maybe this should work meantime? I use a mod, called "Metar" in MSFS which has its own menu-button.
I was referring to the Simconnect menu, the one that appears after you select some operation, the icons on the top menu would be a replacement for the top "Addons" menu anyway, which calls features less used in flight, like the airplane and the scenery configuration editor, which will then have their own UI, so those won't work in VR anyway, but I doubt you would want to do editing of a parking spot with all those text entry fields with your glasses on and no easy access to the keyboard.
About the top menu, the problem with that approach right now is that it works because an add-on redefines a default file from the html-ui to add its button, but the problem is that no more than a single add-on can do that because, the moment another add-on will do the same, only one of them would show, since they both redefined the same default ui file.
Also, the most important menu in GSX is the Simconnect menu, and that requires to be dynamic, with entries that change depending on what is being used or the airport ( the ever changing parking list, for example, which also list if a parking is taken by an AI or not. ). Our current solution works, just not in VR, but we are fairly sure the "proper" solution should eventually come, since Asobo confirmed it with us, they simply haven't got us any release date.
It's also possible they might expose the whole Developer mode UI, which is based on a fairly standard open source UI called imGUI, so all 3rd party add-on might eventually be able to offer an unified UI in-game that would integrate better with the sim, but that might be something more down the road, we expect to first get replacements for the existing Simconnect text functions, which were used to create menus and the top text bar info first, and eventually a complete UI later on.
But in the meantime, we can work and test GSX with our temporary UI and, in case we'll complete GSX before Asobo adds menu support via Simconnect, we can always release it with it, and update it later on to add VR compatibility.
Switching from our custom menu system back to the default Simconnect used in FSX/P3D it's just a few lines of code change for us, since the whole GSX code is entirely abstracted and wrapped to Python language so, the scripts that make all the bulk of what GSX does don't even know how the menu is being used.
