it is also broken in operaGX latest build if you enable media foundation clear in opera://flags, only working with Media Foundation for Clear Rendering Strategy flag enable frame server, all other options cause black screen during video popout, but i think better to use media foundation clear default strategy + Disable Video Popout Redesign, there's some problems in youtube with frame server option, sometimes during Playlists new video won't start and need page refresh, so i think better to use Disable Video Popout Redesign flag, old method working fine without any bugs