Bug 502439

Summary: Rendering artefacts in KDE programs after upgrading to Plasma 6.3.4 and Qt 6.9.0
Product: [Plasma] kwin Reporter: Frederick Zhang <frederick888>
Component: generalAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DOWNSTREAM    
Severity: normal    
Priority: NOR    
Version First Reported In: git-stable-Plasma/6.3   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: Dolphin screenshot
System Settings screenshot
Dolphin screenshot

Description Frederick Zhang 2025-04-05 06:53:56 UTC
Created attachment 180021 [details]
Dolphin screenshot

SUMMARY
Rendering artefacts in KDE programs after upgrading to Plasma 6.3.4 and Qt 6.9.0.

Other Qt programs like KeePassXC didn't seem to have this issue. I didn't have this issue in GTK programs either.

The issue is now gone after rolling back. So it's not a hardware problem.

STEPS TO REPRODUCE
1. Open Dolphin or System Settings
2. Switch between tabs

OBSERVED RESULT
Rendering artefacts

EXPECTED RESULT
No rendering artefacts

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux, tested both kernel 6.12.21 LTS and 6.13.8
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.12.0
Qt Version: 6.9.0
nvidia-dkms: 570.133.07-1

ADDITIONAL INFORMATION
Comment 1 Frederick Zhang 2025-04-05 06:54:24 UTC
Created attachment 180022 [details]
System Settings screenshot
Comment 2 Frederick Zhang 2025-04-05 06:55:11 UTC
Created attachment 180023 [details]
Dolphin screenshot
Comment 3 Frederick Zhang 2025-04-05 06:57:11 UTC
Forgot to mention that I was using theme https://github.com/vinceliuice/Layan-kde.

I should've probably tested Breeze before rolling back... Please let me know if I should test it out.
Comment 4 Frederick Zhang 2025-04-05 07:40:16 UTC
Breeze and Breeze Dark didn't have this issue. I did a partial upgrade with only Plasma and Qt (Plasma failed to start after upgrading only Qt), so it was not caused by some other software in the full upgrade.

I have reported this to https://github.com/vinceliuice/Layan-kde/issues/71. I'm marking this ticket as resolved for now, unless it's later discovered to be a Plasma issue, then feel free to re-open. Sorry for the noise.
Comment 5 Frederick Zhang 2025-04-17 11:02:13 UTC
Potential cause: https://bugreports.qt.io/browse/QTBUG-135867