Bug 467998

Summary: Alt+tab freezes desktop
Product: [Plasma] kwin Reporter: Piotr <piotr>
Component: tabboxAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED FIXED    
Severity: crash CC: kde, nate, plasma-bugs-null
Priority: NOR    
Version First Reported In: 5.24.7   
Target Milestone: ---   
Platform: Kubuntu   
OS: Linux   
Latest Commit: Version Fixed/Implemented In: 5.27
Sentry Crash Report:
Attachments: attachment-2287736-0.html

Description Piotr 2023-03-31 11:37:26 UTC 
SUMMARY
Sometimes when switching between windows screen freezes - I can stil use my mouse, but clock is frozen, I can't use alt-tab anymore, nor click on any application from app launcher.
Logout/reboot helps.

Alternatively I'm executing script from another TTY, which unfeezes the screen, but doesn't bring back functionality of alt+tab:

```
#!/bin/bash
export DISPLAY=:0
pkill plasmashell ; sleep 1 ; systemctl --user start plasma-plasmashell.service
kwin --replace &
plasmashell --replace
killall plasmashell
kstart5 plasmashell
```

STEPS TO REPRODUCE (this happens randomly):
1.  alt+tab during work

OBSERVED RESULT
Frozen desktop.

EXPECTED RESULT
Switched window.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
KDE Plasma Version: 5.24.7
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3
Kubuntu 22.04.2

ADDITIONAL INFORMATION
n/a
Comment 1 David Edmundson 2023-07-05 10:01:08 UTC 
If something is frozen, we need a backtrace of it so we can figure out what's going on. Can you please attach a backtrace of the crash using the coredumpctl command-line program, as detailed in https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports#Retrieving_a_backtrace_using_coredumpctl?
Thanks!
Comment 2 Nate Graham 2023-07-05 13:54:12 UTC 
Also, please re-test with Plasma 5.27, as 5.24 is no longer in support at this point in time. Thanks!
Comment 3 Piotr 2023-07-05 15:31:21 UTC 
Created attachment 160089 [details]
attachment-2287736-0.html

This bug is gone in 5.27. Thanks.

On Wed, Jul 5, 2023 at 3:54 PM Nate Graham <bugzilla_noreply@kde.org> wrote:

> https://bugs.kde.org/show_bug.cgi?id=467998
>
> --- Comment #2 from Nate Graham <nate@kde.org> ---
> Also, please re-test with Plasma 5.27, as 5.24 is no longer in support at
> this
> point in time. Thanks!
>
> --
> You are receiving this mail because:
> You reported the bug.
Comment 4 Nate Graham 2023-07-05 15:38:49 UTC 
Great, thanks. Let's call it fixed.