I am experiencing this bug as well and hopefully can provide some additional information.
Firstly, steps to reproduce (fresh profile, 2019-30-12 nightly build):
- Restart FF
- Suspend computer
- Wake the computer
- Go to YouTube and play any video. After a few seconds interface will start disappearing
Here's a screenshot: https://i.postimg.cc/PqCVzLMP/firefox-bug2.png
layers.acceleration.force-enabled set to
true is crucial for this to happen. Similarly to OP, with this setting set to
false (which is the default) I am experiencing lots of screen tearing. I started experiencing this problem after upgrading from previous ESR release (based on 60.x branch) to the latest ESR release (based on 68.x) branch, which means this must have been introduced somewhere in between. Also, it sufices to just put computer to sleep, it doesn't have to be for hours. Finally, this only starts to happen after playing a video (something on YT or a webm video) - as long as I just browse pages without videos everything displays fine.
My platform is the latest Debian Buster 10.2 with NVidia proprietary driver, version 418.74. Let me know if more information is required. Right now I am seriously considering downgrading back to an older ESR, since the screen tearing is just so bad (with
false) and I can't afford to restart FF every time I put my laptop to sleep (which is mutliple times a day).