Bug 482669 - Taskbar icons are moving to the left on hover with QT_QUICK_BACKEND=software
Summary: Taskbar icons are moving to the left on hover with QT_QUICK_BACKEND=software
Status: RESOLVED UPSTREAM
Alias: None
Product: plasmashell
Classification: Plasma
Component: Panel (show other bugs)
Version: 6.0.1
Platform: Arch Linux Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL: https://bugreports.qt.io/browse/QTBUG...
Keywords: qt6
: 488072 494912 (view as bug list)
Depends on:
Blocks:
 
Reported: 2024-03-07 09:07 UTC by Balló György
Modified: 2024-11-12 16:19 UTC (History)
7 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:

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Screenshot of the bug (9.81 KB, image/png)
2024-03-07 09:07 UTC, Balló György 		Details
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Description Balló György 2024-03-07 09:07:46 UTC 
Created attachment 166553 [details]
Screenshot of the bug

SUMMARY
When I move the mouse over the icons on the taskbar, they move to the left.


STEPS TO REPRODUCE
1. Set QT_QUICK_BACKEND=software environment variable in /etc/environment, then restart.
2. Start Plasma (Wayland) or Plasma (X11) session.
3. Move the mouse over the icons on the taskbar.

OBSERVED RESULT
Icons are moved to the left side.

EXPECTED RESULT
Icons should stay at their positions.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
KDE Plasma Version: 6.0.1
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Comment 1 Nate Graham 2024-03-07 21:20:02 UTC 
`QT_QUICK_BACKEND=software` isn't a supported way to run KDE software; there be dragons.
Comment 2 Balló György 2024-03-07 21:21:15 UTC 
But why? It was worked in Plasma 5.
Comment 3 Nate Graham 2024-03-07 21:36:04 UTC 
It was never supported; if it worked in Plasma 5 that was random chance.

Please stop using it and then submit bug reports for the issues you encounter that make you want to use it. We want reports about bugs in our features, not reports about bugs in your workarounds for the bugs in our features. :)
Comment 4 Karl Ove Hufthammer 2024-05-16 18:06:51 UTC 
I’m experiencing the exact same problem, and I am *not* using QT_QUICK_BACKEND=software (as far as I’m aware). Whenever I hover over a button on the panel (either a taskbar icon or a different icon), it moves to the left, overlapping the application launcher.
Comment 5 Karl Ove Hufthammer 2024-05-16 18:08:25 UTC 
And here’s some more system information:

Operating System: openSUSE Tumbleweed 20240514
KDE Plasma Version: 6.0.4
KDE Frameworks Version: 6.2.0
Qt Version: 6.7.0
Kernel Version: 6.8.9-1-default (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i5-2500 CPU @ 3.30GHz
Memory: 15.6 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 1060 3GB/PCIe/SSE2
Manufacturer: MSI
Product Name: MS-7673
System Version: 1.0
Comment 6 Karl Ove Hufthammer 2024-06-02 17:13:45 UTC 
Turns out that I *was* using software-based rendering after all. However, I did *not* manually enable it (e.g., using QT_QUICK_BACKEND=software). But for some reason (a crash?), Plasma decided to fall back to software-based rendering (rebooting didn’t help). I later got a notification about this. After reenabling OpenGL-based rendering, the problem with taskbar icons moving to the left disappeared.
Comment 7 Nate Graham 2024-06-12 13:29:50 UTC 
It's a Qt bug unfortunately: https://bugreports.qt.io/browse/QTBUG-123799
Comment 8 Nate Graham 2024-06-12 13:29:54 UTC 
*** Bug 488072 has been marked as a duplicate of this bug. ***
Comment 9 Balló György 2024-07-23 11:29:16 UTC 
Still happens with Qt 6.8.0beta2.
Comment 10 Balló György 2024-10-03 19:28:38 UTC 
Still happens with Qt 6.8.0rc1.
Comment 11 Zamundaaa 2024-10-17 10:54:17 UTC 
*** Bug 494912 has been marked as a duplicate of this bug. ***