Windows flicker when resizing with mouse (GNOME-Shell - Xorg & Budgie)

[Sam Lane]

When resizing a window with the mouse by dragging the edge or corner, the window begins to flicker. It only flickers when actively being resized, and when I stop dragging, it looks normal. This behavior is does not occur on same pc in 20.04. Sometimes the flickering is black, sometimes the flickering makes the wallpaper visible, even when there is a window behind the window being resized.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: mutter (not installed)
ProcVersionSignature: Ubuntu 5.8.0-18.19-generic 5.8.4
Uname: Linux 5.8.0-18-generic x86_64
ApportVersion: 2.20.11-0ubuntu45
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: Budgie:GNOME
Date: Tue Sep 22 14:48:00 2020
InstallationDate: Installed on 2020-09-22 (0 days ago)
InstallationMedia: Ubuntu-Budgie 20.10 "Groovy Gorilla" - Alpha amd64 (20200921)
SourcePackage: mutter
UpgradeStatus: No upgrade log present (probably fresh install)

[fossfreedom (fossfreedom)]

Note - this affects GNOME-Shell on Xorg as well.

Confirmed with intel i915 driver.

GNOME-Shell on Wayland there are no window flicker

So most probably a regression in mutter (since budgie and GNOME-Shell share the same window manager) in the X11 handling.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[fossfreedom (fossfreedom)]

Should note - testing mutter package 3.38.0-1ubuntu1

[fossfreedom (fossfreedom)]

I do not see any window flickering with QEMU hosting 20.10 guest. So specific to intel i915? Sorry - I cannot test radeon or Nvidia.

[Stéphane (steph-pak)]

I can confirm this problem with Ubuntu 20.10, NVIDIA (prime mode OnDemand) with Xorg.
Windows flicker when resizing any windows.