Hello again ;p
Ok i see, i checked the UI and yes the apply button wasn't there on 4:3 preview mode.
I moved it to make it appear. Even if it work, i suggest you to play on 16:9 resolution to have optimal experience.
( Maybe you should chose 1280x720, uncheck fullscreen and apply in your case )
I did quick fix cause we are currently working on our new project and making grow our company.
So let me know if it helped ( We will consider to replace the download on Check-In page if yes )
You can find the build with quick fix there ( link available during 1 week )
https://we.tl/t-TxTEt09qGG
Okult Studio Team ;)
https://okultstudio.com/