Bug 420442

Summary:	Pressing Alt+Tab with no open windows, while window is loading, makes everything disappear
Product:	[Plasma] kwin	Reporter:	nyanpasu64 <nyanpasu64>
Component:	core	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UNMAINTAINED
Severity:	normal	CC:	nate
Priority:	NOR
Version First Reported In:	5.18.4
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description nyanpasu64 2020-04-23 05:01:30 UTC

SUMMARY
If you press Alt+Tab when no windows are open, and release it after a window opens, all windows and panels disappear.

STEPS TO REPRODUCE
1. Launch Firefox. For me, it takes about a second before the window appears.
2. Immediately press Alt+Tab and hold Alt. The window switcher will say "Show Desktop".
3. Once Firefox loads, the window switcher will say "Mozilla Firefox". Release Alt.

OBSERVED RESULT
Everything but the wallpaper and cursor disappears. If you open another Firefox window using Ctrl+N, it's also invisible. Windows can be interacted with, using keyboard or mouse.

EXPECTED RESULT
Windows don't become all invisible.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20200421
KDE Plasma Version: 5.18.4
KDE Frameworks Version: 5.69.0
Qt Version: 5.14.1
Kernel Version: 5.6.4-1-default
OS Type: 64-bit
Processors: 4 × Intel® Core™ i5-6200U CPU @ 2.30GHz
Memory: 7.6 GiB of RAM

ADDITIONAL INFORMATION
I think this occurs in both X11 and Wayland.

Comment 1 nyanpasu64 2021-06-17 01:02:06 UTC

This still happens in Plasma 5.22.1 on Arch Linux, on X11. Restarting kwin fixes the bug.

Comment 2 David Edmundson 2023-09-06 10:39:08 UTC

This bug was reported against an outdated version of KWin. We have made many changes since the. 
If the issue persists in newer versions can you reopen the bug report updating the version number.