The problem

When Firefox plays a video e.g. from Youtube and I swtich to full-screen view, then after a few seconds the video freezes while the audio is keep playing.

Workaround

When I remove the noroot option in the firefox.profile, then full-screen works fine.

Environment

Firefox version: 58
Xorg server: 1.19.6
Firejail version: 0.9.52
OS: Arch Linux with kernel 4.14.15