Thanks. That is a very helpful screenshot. It appears that only recently changed widgets/actors are rendered correctly. So this suggests a bug in mutter's buffer age logic, or the graphics driver.
Can you please: 1. Run 'lspci -k' and attach the output. 2. Run 'dmesg' (after the problem has occurred) and attach the output here. ** Package changed: gnome-shell (Ubuntu) => mutter (Ubuntu) ** Also affects: linux (Ubuntu) Importance: Undecided Status: New ** Also affects: mesa (Ubuntu) Importance: Undecided Status: New ** Changed in: linux (Ubuntu) Status: New => Incomplete ** Changed in: mesa (Ubuntu) Status: New => Incomplete ** Changed in: mutter (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/1752145 Title: system freeze after full screen video viewing with Xorg on ultrawide monitor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1752145/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp