Hey @Portisch,
I just had the time to test your implementation and I am speechless. You have outdone yourself! Not only did you fix the GUI, you fixed 3D MVC for external AND internal subtitles and they even work with the depth setting of Kodi. They work absolutely flawlessly now. As an added bonus, at least my TV now kicks out of 3D correctly after a file ends.
This is quite spectacular, as I think, there are no issues left to tackle for 3D on NG with hdmitx20.
@Astrotrain : Maybe worth adding that “internal and external subtitles incl. 3D depth settings” work on NG in the Ugoos Guide?