Bug 475375

Summary:	Ghost duplicate buttons in Task Manager
Product:	[Plasma] kwin	Reporter:	martin-kokos
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	kde, nate
Priority:	NOR
Version First Reported In:	5.27.8
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=471315
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Duplicates in taskbar Empty ghost tasks

Description martin-kokos 2023-10-08 14:50:37 UTC

Created attachment 162165 [details]
Duplicates in taskbar

SUMMARY
***
NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols.
See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***


STEPS TO REPRODUCE
1. Boot
2. Start Firefox which restores multiple windows at once very quickly
3. Happens almost always on fresh boot

OBSERVED RESULT
Have duplicates in Task Manager/task bar. See screenshot. The Firefox has opened 8 windows plus 1 Alacritty, There are duplicates for the Firefox windows
The duplicates are always on the left.
There can be more duplicates. See screenshot: 1 true Alacritty, two duplicates.
Sometimes some of them disappear but not all after some interactions with taskbar.
Sometimes they turn blank or just the title is clears.
right clicking them shows a menu with grayed out close option.

EXPECTED RESULT
No duplicates or ghost windows in task bar

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 5.27.8
(available in About System)
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.10

ADDITIONAL INFORMATION
Also sometimes random crashes of kwin when activating a window via task bar which might be related.

Comment 1 martin-kokos 2023-10-08 14:51:27 UTC

Created attachment 162166 [details]
Empty ghost tasks

Comment 2 David Redondo 2023-10-11 06:58:51 UTC

Hi  what a weird bug. As one of the symptoms is a crash could you attach the backtrace 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?

Additionally or alternatively maybe you can attach a wayland log of plasmashell to do that run
WAYLAND_DEBUG=1 plasmashell
from a terminal and attach the output if the situation with duplicate tasks occurs. thank you!

Comment 3 martin-kokos 2023-10-17 14:25:27 UTC

I was able to recompile with debug symbols have submitted a crash report: https://bugs.kde.org/show_bug.cgi?id=475742

Comment 4 martin-kokos 2023-10-24 07:10:53 UTC

I have tried removing the Power widget as mentioned here https://bugs.kde.org/show_bug.cgi?id=471315#c15
and the crashes as well as this bug appear to be resolved.

Comment 5 David Redondo 2023-10-24 12:30:00 UTC

How very weird.