Bug 503825

Summary: Wobbly Window effect causes graphical glitches when maximising (by dragging to the top of the screen)
Product: [Plasma] kwin Reporter: madness742
Component: effects-variousAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED INTENTIONAL    
Severity: normal CC: nate
Priority: NOR    
Version First Reported In: 6.3.4   
Target Milestone: ---   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Showcase of the bug.
Wobbliness set to max.

Description madness742 2025-05-06 05:03:23 UTC
Created attachment 180979 [details]
Showcase of the bug.

SUMMARY
Wobbly Window effect causes graphical glitches when maximising by dragging the window to the top of the screen. Using the maximise button is not affected.

STEPS TO REPRODUCE
1. Enable Wobbly Windows (System Settings -> Desktop Effects -> Wobbly Windows).
2. Drag a window to the top of the screen and *quickly* release it.

OBSERVED RESULT
The effect becomes glitched upon releasing the left mouse button.

EXPECTED RESULT
The effect should appear the same as when using the maximise/restore button.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora Linux 42
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.13.0
Qt Version: 6.9.0

ADDITIONAL INFORMATION
- When restoring the window size by dragging (as opposed to using the button), it also glitches.
- The glitch does not occur when waiting around 1 second before releasing the left click to maximise, but restoring the window size by dragging still appears glitched.
Comment 1 Nate Graham 2025-05-06 15:52:16 UTC
That's not a graphical glitch, it's simply a side effect of the wobbling. :)
Comment 2 madness742 2025-05-07 02:09:10 UTC
(In reply to Nate Graham from comment #1)
> That's not a graphical glitch, it's simply a side effect of the wobbling. :)

I do want to add that maximising looks a lot worse compared to snapping a window into a zone (holding shift while dragging a window). When I disable "Wobble when resizing" under the effect settings, it behaves similar to the snapping window animation. 

The difference is very easily noticeable when the wobbliness is set to max.

Creating a floating tile that covers the entire screen with 0 padding also prevents the window from appearing on my second monitor when restoring the window size by dragging. 

Could you take a look at the next video attachment and tell me if this is expected behaviour? Thanks!
Comment 3 madness742 2025-05-07 02:12:51 UTC
Created attachment 181011 [details]
Wobbliness set to max.
Comment 4 Nate Graham 2025-05-07 03:03:35 UTC
It's expected, yeah.