Bug 468257

Summary:	Maximizing then tiling a window, causes it to show stale stretched contents when other windows are maximized or unmaximized
Product:	[Plasma] kwin	Reporter:	nyanpasu64 <nyanpasu64>
Component:	compositing	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	REPORTED ---
Severity:	normal
Priority:	NOR
Version First Reported In:	5.27.3
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Photo of non-maximized Dolphin window showing a stale maximized image while maximizing any other window

Description nyanpasu64 2023-04-07 16:56:27 UTC

SUMMARY
Some windows will enter a state where they show normal contents initially, but the animations to maximize/unmaximize other windows cause them to show stale contents.

STEPS TO REPRODUCE
1. Maximize nearly any window (browsers, Qt5, GTK3/4 apps work, glxgears works, xterm doesn't).
2. Use Super+Arrow to tile it to half the screen, without an animation.
a. You can stack Super+Up+Left to tile it to a quarter screen, or Super+Left+Left to unmaximize the window without an animation.
3. Maximize or minimize any other window.

OBSERVED RESULT
The first window (which you tiled out of maximize) shows stale contents from the last time it was maximized, for the duration of the second window's (un/)maximize animation. Sometimes part of the window remains stale after the animation completes.

When no animation is playing, you can interact with the stale window's contents normally. But if you maximize another window again, the contents revert to the same stale texture.

EXPECTED RESULT
Windows do not show corrupted contents when un/maximizing other windows.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.27.3
KDE Frameworks Version: 5.104.0
Qt Version: 5.15.8
Kernel Version: 6.2.9-zen1-1-zen (64-bit)
Graphics Platform: X11
Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor
Memory: 15.5 GiB of RAM
Graphics Processor: AMD Radeon RX 570 Series
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: B550M DS3H

ADDITIONAL INFORMATION
Unsure if related to Bug 450301?

Comment 1 nyanpasu64 2023-04-17 06:10:22 UTC

I can get the same graphical corruption in maximized windows. I'm not sure how to trigger that.

Comment 2 nyanpasu64 2023-05-06 06:50:47 UTC

Created attachment 158734 [details]
Photo of non-maximized Dolphin window showing a stale maximized image while maximizing any other window

I've gotten the same corruption for restored (not tiled or maximized) windows. Here's a screenshot of the bug in action. The Dolphin window always shows stale maximized content while I maximize or unmaximize other window, and the content is partially updated once the animation finishes.

The bug does not end when I interact with Dolphin's contents, move or resize the window, or tile it. It ends when the window is maximized, and can be triggered again on demand by maximizing the victim, tiling to a side, then tiling again to the same side so the window exits tiled mode.

I still do not know how to trigger this corruption for maximized windows. It does not occur for windows which are maximized, or maximizing and restarting Kotatogram Desktop so it starts out maximized.

Comment 3 nyanpasu64 2023-05-20 19:23:26 UTC

Also happens on Wayland.

Operating System: Arch Linux 
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.106.0
Qt Version: 5.15.9
Kernel Version: 6.3.2-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor
Memory: 15.5 GiB of RAM
Graphics Processor: AMD Radeon RX 570 Series
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: B550M DS3H