idk if you still fiddle around with this but, i happened to come acrossed it and used it for the win10 ver.1.12. The reason for this is so i can play minecraft with my friends who are on console. i tried using this program for a texture pack called quadral and everything works but the ui. for whatever reason, when i don't have the "Require players to accept resource packs to join", everything works perfectly fine, but when i turn it on, the ui doesnt work. it could be because the win10 ver has awkward pacing in what is updated etc.
Nvm i fixed it to some extent