Windows get wrong z-index and flickering decoration halo

[herrsaalfeld]

Frequently, windows such as the new text editor, or the nautilus file browser, or modal dialogs seem to have an in valid z-index, i.e. I cannot click the title bar, and the window is virtually behind everything. The window also has a flickering halo full of garbage from other screen areas which looks like missallocated texture memory? It is possible to bring the window into the foreground, bu e.g. TABing through the applications but it cannot be used because other windows that are 'behind' it capture the mouse events through this window. This can happen with many Windows at the same time, typically after sleep-wake. The Windows can be rescued into normal state by using keyboard shortcuts to maximize-minimize, after which everything is fine. The z-index is correct, mouse events are captured and the decorations look perfect.

This started happening with Ubuntu 22.10 and is still present in 23.04, so I assume that it is a bug in Gnome 43? This happens regularly after sleep wake which, in my case, often comes with a zoom switch between 100% (external monitor on dock) and 200% (internal HiDPI laptop screen). I am running Ubuntu on xorg, not Wayland, because screen-sharing individual windows with Zoom does not work on Wayland. I am observing this most frequently with Snap apps such as Nautilus and the new text editor, but also Evolution dialogs have come up with this. May be a timing issue that manifests more frequently with the slower snap apps?

I understand that this bug-report is unsatisfying in how to reproduce this, and what exactly the outcome is, but it is pretty random in nature and I can only report the visual/ GUI outcome. I am happy to provide additional input as requested.
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ProblemType: Bug
ApportVersion: 2.26.1-0ubuntu2
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
DisplayManager: gdm3
DistributionChannelDescriptor:
 # This is the distribution channel descriptor for the OEM CDs
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-focal-amd64-20200502-85
DistroRelease: Ubuntu 23.04
InstallationDate: Installed on 2021-05-04 (765 days ago)
InstallationMedia: Ubuntu 20.04 "Focal" - Build amd64 LIVE Binary 20200502-05:58
Package: gnome-shell 44.1-0ubuntu1
PackageArchitecture: amd64
ProcEnviron:
 LANG=en_US.UTF-8
 PATH=(custom, no user)
 SHELL=/bin/bash
 TERM=xterm-256color
 XDG_RUNTIME_DIR=<set>
ProcVersionSignature: Ubuntu 6.2.0-20.20-generic 6.2.6
RelatedPackageVersions: mutter-common 44.1-0ubuntu1
Tags: lunar
Uname: Linux 6.2.0-20-generic x86_64
UpgradeStatus: Upgraded to lunar on 2023-04-26 (43 days ago)
UserGroups: adm cdrom dip docker lpadmin plugdev sambashare sudo
_MarkForUpload: True

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Libera.chat.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/2023209/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

  apport-collect 2023209

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Daniel van Vugt (vanvugt)]

Also it sounds like you are describing bug 2013216 and bug 2020674, both of which have had fixes released in the past week. So please try updating your system:

  sudo apt update
  sudo apt full-upgrade

and reboot. The packages you need to get the fixes are:

  libmutter-12-0 version 44.1-0ubuntu1
  libgtk-4-1 version 4.10.3+ds-0ubuntu1

[herrsaalfeld (herrsaalfeld)]

apport information

[herrsaalfeld (herrsaalfeld)]

apport information

[herrsaalfeld (herrsaalfeld)]

apport information

[herrsaalfeld (herrsaalfeld)]

apport information

[herrsaalfeld (herrsaalfeld)]

apport information

[herrsaalfeld (herrsaalfeld)]

Thanks! I updated as advised and the bug is still present after a full reboot. I was also able to trigger it by changing the zoom-level in the display settings dialog. The two other bugs do not ring a bell, I do not have an NVIDIA graphics card and it does not depend on the complexity of the title bar. I also wanted to mention that this is a symptomatic desktop experience report report and I have no idea which package causes it.

I hope this helps.

[herrsaalfeld (herrsaalfeld)]

before changing scale from 200% to 100%

[herrsaalfeld (herrsaalfeld)]

Screenshot after changing scale from 200% to 100%. Text editor window and display settings window show the described bug and do not react to mouse input as expected. Terminal and browser remained normal. Ubuntu's screen capture tool saves the buggy halo around the windows as transparent. The web-browser displays this as gray, please view in an image viewer or Gimp. This may be important?

[Daniel van Vugt (vanvugt)]

The above issue is bug 1924689.

To avoid further confusion, please describe what other problem still remains. And remember to always log a separate bug for each problem.

[herrsaalfeld (herrsaalfeld)]

Thanks for the find!