In Jammy Jellyfish (Thunderbird 91.5.0, GNOME Shell 40.5) when this bug occurs it also cause the Thunderbird window to not display at all. The application dock shows that it is open, but there is no way to get to it unless you right click the dock icon and open a new window.
Sharing here as I believe it is related. Hopefully the fix committed will take care of this. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/1933996 Title: Alt-tab stops switching windows [JS ERROR: TypeError: window is null _createWindowClone@resource:///org/gnome/shell/ui/altTab.js:29:27] Status in GNOME Shell: Unknown Status in mutter package in Ubuntu: Fix Committed Bug description: When a new Wayland session is created from a login, Alt-tab works as expected to change windows. After sometime Alt-tab fails to do anything (super-tab still works to change applications) and the following error is created in syslog: gnome-shell[777718]: JS ERROR: TypeError: window is null#012_createWindowClone@resource:///org/gnome/shell/ui/altTab.js:29:27#012_init@resource:///org/gnome/shell/ui/altTab.js:1004:34#012_init@resource:///org/gnome/shell/ui/altTab.js:1045:24#012_init@resource:///org/gnome/shell/ui/altTab.js:568:30#012_startSwitcher@resource:///org/gnome/shell/ui/windowManager.js:2069:24 The only workaround I have found is to logout and log back in, however after some time the error repeats itself. Ubuntu 21.04 gnome-shell: Installed: 3.38.4-1ubuntu3~21.04.1 ProblemType: Bug DistroRelease: Ubuntu 21.04 Package: gnome-shell 3.38.4-1ubuntu3~21.04.1 ProcVersionSignature: Ubuntu 5.11.0-22.23-generic 5.11.21 Uname: Linux 5.11.0-22-generic x86_64 ApportVersion: 2.20.11-0ubuntu65.1 Architecture: amd64 CasperMD5CheckResult: unknown CurrentDesktop: ubuntu:GNOME Date: Tue Jun 29 10:53:32 2021 DisplayManager: gdm3 InstallationDate: Installed on 2020-11-11 (230 days ago) InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022) RelatedPackageVersions: mutter-common 3.38.4-1ubuntu2 SourcePackage: gnome-shell UpgradeStatus: Upgraded to hirsute on 2021-04-27 (62 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/gnome-shell/+bug/1933996/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
