Window switching with Alt-Tab stops working after a while

[Florian]

On Ubuntu 21.04,since around 01 July 2021, Alt-Tab works as usual for a while after logging in, but then stops entirely (that is, it does nothing; the switcher overlay fails to appear, and switching between windows does not work). I made _no_ configuration change, and Alt-Tab continues to be configured in the keyboard shortcuts settings as usual.

This has been described by other users here: https://askubuntu.com/questions/1349544/alttab-stops-working-after-a-while-in-ubuntu-21-04

There seems to be some possible connection to Thunderbird in particular, and the fact that in the left-hand-side launcher (?) / favourites of the Ubuntu desktop, the Thunderbird icon starts behaving strangely, e.g. does not show the open Thunderbird windows when clicking on it ... while other applications work.

[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 Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1934527/+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.]

[Launchpad Janitor (janitor)]

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

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1933996, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.

[Krzysztof Raczkowski (raczkow)]

I've noticed, that problems start just after I create a new message in Thunderbird and press Send button. Message is sent, its windows is closed, and from this time dock and alt+tab is broken.

[first second (ljkasglbniaf)]

I believe that the bug is related to Wayland. It can be fixed by not using it as described here: https://askubuntu.com/questions/1349544/alttab-stops-working-after-a-while-in-ubuntu-21-04/1359821#1359821

[Daniel van Vugt (vanvugt)]

Please discuss the issue in bug 1933996 or https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3456