Bug 504283 - Widget popups are slow to open on X11
Summary: Widget popups are slow to open on X11
Status: RESOLVED UPSTREAM
Alias: None
Product: kwin
Classification: Plasma
Component: platform-x11-standalone (other bugs)
Version First Reported In: 6.3.90
Platform: openSUSE Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: efficiency-and-performance, regression, X11-only
Depends on:
Blocks:
 
Reported: 2025-05-15 17:33 UTC by Fushan Wen
Modified: 2025-06-10 14:26 UTC (History)
1 user (show)

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Description Fushan Wen 2025-05-15 17:33:26 UTC 
SUMMARY
All widget popups delay to open after clicking on them. Seems to only happen on X11 and can be worked around by using other window compositors.

STEPS TO REPRODUCE
1. Click Kickoff, system tray and digital clock to open their full representations

OBSERVED RESULT
There is a significant delay before the widget popup pops up.

EXPECTED RESULT
No delay

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 6.3.80
KDE Plasma Version: kwin6-x11 at 77e54d3b
KDE Frameworks Version: 6.15
Qt Version: 6.9.0

ADDITIONAL INFORMATION
Comment 1 Fushan Wen 2025-05-16 14:05:23 UTC 
My assumption is kwin only paints a window after finishing a XSync event, but a recent change in QQuickWindow or elsewhere delays the sync event.
Comment 2 Bug Janitor Service 2025-05-17 09:30:13 UTC 
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin-x11/-/merge_requests/31
Comment 3 Bug Janitor Service 2025-05-17 09:50:46 UTC 
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/5482