https://bugs.kde.org/show_bug.cgi?id=506854
Bug ID: 506854
Summary: Window may randomly become invisible after activating
"Peek at Desktop", disabling windowaperture makes it
visible again
Classification: Plasma
Product: kwin
Version First 6.4.2
Reported In:
Platform: Arch Linux
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: general
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
SUMMARY
Windows sometimes become invisible when switching virtual desktops or peeking
the desktop. It happens relatively rarely and randomly, but often enough to be
annoying. Until recently, I didn't know any workarounds. The only way to
continue work was to either close and re-open the window, or migrate all tabs
to a new window if the application supports tabs (I usually hit the bug either
on Firefox or Konsole).
I accidentally found that unloading the "windowaperture" effect in Kwin Debug
Console makes the window visible again.
I first noticed the bug at least two years ago. I have not reported it until
today because I couldn't reliably reproduce it. I'm not sure if I encountered
it when using X11, I currently use Wayland.
STEPS TO REPRODUCE
1. Make sure windowaperture effect is loaded in in Kwin debug console.
2. Go to any window, hold "Peek at desktop" Window Management shortcut (I think
Meta+D is the default) for ~2 minutes, usually 30 seconds is enough. EPILEPSY
WARNING: the window and desktop may alternate very fast causing a strobe-like
effect.
OBSERVED RESULT
The window should become invisible after some hide/unhide cycles. The window is
still there, can be activated and interacted with, is visible in window
switcher, overview etc... It's just invisible on the desktop, regardless of
whether it's activated or not. Switching to it, or hitting Meta+D does not make
it visible again.
It can be made visible again by unloading the windowaperture effect in KWin
debug console. Loading the effect after unloading it does not make the window
invisible again (unless the steps from reproduce are repeated).
EXPECTED RESULT
The window should stay visible or become visible after quitting the "Peek
desktop" state.
SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux, 6.15.4-arch2-1, last upgrade on
2025-07-05T14:28:06+0200
KDE Plasma Version: 6.4.2 (also reproducible on 6.1.3)
KDE Frameworks Version: 6.15.0 (also reproducible on 6.4.0)
Qt Version: 6.9.1 (also reproducible on 6.7.2)
KWin Version: 6.4.2 (also reproducible in 6.1.3)
ADDITIONAL INFORMATION
I was able to reproduce the bug on fullscreen, maximized and unmaximized
windows. Same with windows with and without hidden titlebar/frame. I don't have
a taskbar or a topbar, windows are usually maximized.
I only have the "Desktop Change OSD" KWin script activated.
Activated desktop effects: Invert, Background contrast, Blur, Desaturate
Unresponsive Applications, Dialog Parent, Dim Screen for Administrator Mode,
Overview.
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