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After upgrading to Ubuntu 21.04 "hirsute", changing of program windows with ALT+TAB stops working. After a while I am not able to jump between programs.

Also the red dots in the favorites bar which shows that a program is open/active are not vanishing after closing / shutting down the program any more, at least for Thunderbird.

~$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=21.04
DISTRIB_CODENAME=hirsute
DISTRIB_DESCRIPTION="Ubuntu 21.04"
~$ echo $XDG_CURRENT_DESKTOP
ubuntu:GNOME

Does anybody know how to get my workflow back?

Addition: it's not ALT+TAB which is not working. It is only "change windows". If I switch ALT+TAB to "change windows immediately" in the gnome settings for keyboard shortcuts, it works to change the windows directly. After a reboot and changing it back to "change windows" (with having a choice through all open programs) it works for a while then stops working again after some time. Strange...

Jochen Haßfurter
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4 Answers4

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I was able to resolve the problem, yeah! :) I had exactly the same problem, i.e., both alt+tab not working and the red bullets at the thunderbird icon not disappearing.

Reading through that question I found out that it's related to Wayland not working correctly. Wayland is a display server protocol used by Ubuntu 21.04. Its predecessor used Xorg instead.

This is how you can confirm that Wayland is used -- and how you can change it. Note that my response is copied from the stackoverflow entry above, so please like that response as well if you found my response helpful!

  1. Type echo $XDG_SESSION_TYPE --> It will print Wayland (I suppose).
  2. Type sudo gedit /etc/gdm3/custom.conf --> You will find the entry #WaylandEnable=false, from which you will have to remove the comment symbol, i.e., remove the #. I assume that switches back to Xorg.
  3. Save, reboot, and enjoy alt+tab again! :)

(FYI: In my case, Ubuntu freezed altogether at some point, and it seems as if this is now resolved as well.)

Prof.Chaos
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    Thank you so much. This also fixes my issues with Citrix Workspace remote desktop and Alt+Tab – johnk Aug 28 '21 at 08:14
  • You are very welcome. :) Happy to learn that it even solved further problems! – Prof.Chaos Aug 28 '21 at 11:58
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    Although my fiddly workaround for my problem worked (see my answer), I have now switched from Wayland to Xorg after all. Somehow it also feels a bit faster. Thanks for the tip! – Steffen Bobek Sep 01 '21 at 09:20
  • I have the same problem with XDG_SESSION_TYPE=x11. – dolmen Dec 21 '21 at 17:49
  • I had the same problem with Ubuntu 21.10. Additionally, I could not scroll in some web pages in Firefox (especially banking web sites). All 3 Problems are solved after switching back to Xorg. – Thomas Jan 24 '22 at 18:24
  • at some unexpected time in the future will an update break this by re-enabling wayland? – Michael May 19 '22 at 15:03
  • I don't know... But is that still relevant? 22.04 has been released anyway! – Prof.Chaos May 20 '22 at 09:37
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    This is solved my other problem https://stackoverflow.com/questions/72512625/dual-monitor-setup-on-citrix-workspace-app-for-linux-is-not-working . thanks @Prof.Chaos – Nasimuddin Ansari Jun 06 '22 at 13:58
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I've been running 21.04 for a couple of months now without issues, but just yesterday, the problem described here started to happen for me, too. Seems to be due to a recent update of something.

Florian Friedrich
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    To add: there does seem something odd about Thunderbird. The behaviour described above of the Favourites Bar / launcher really only happens with Thunderbird, not other applications. Not sure whether it's related to the Task switcher issue, but they do seem to kick in at the same time. – Florian Friedrich Jul 02 '21 at 13:14
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    Filed a bug report: https://bugs.launchpad.net/ubuntu/+bug/1934527 – Florian Friedrich Jul 02 '21 at 17:08
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    Apparently has to do with Thunderbird not properly de-registering an email window after sending mail. So the window switcher gets a null pointer to a window that does not exist, and crashes. – Florian Friedrich Jul 06 '21 at 09:10
  • I have the Alt+Tab issue but I don't use thunderbird. I use another Mozilla product though: Firefox. – dolmen Dec 21 '21 at 17:51
  • @FlorianFriedrich so uh... can't you just restart the switcher? – Michael May 19 '22 at 14:59
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I get the same problem when sending emails with Thunderbird. However, if I press ALT+TAB directly after pressing "Send" in Thunderbird and keep ALT pressed until the mail is sent, then the problem does not occur.

Steffen Bobek
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I'm also affected by this, but this worked, by Jakob Lell:

"I'm also affected by this bug when using Thunderbird but I've found a workaround: Unpin Thunderbird (right click on the icon and "Remove from Favorites"). After that you can still start Thunderbird manually, it won't trigger this bug any more when it is just a normal application (and not a "favorite" application with a fixed place in the Dock)."

Eugenio Perea
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