Bug 505810

Summary:	maximized windows leave small blank space with certain window decorations on large size
Product:	[Plasma] kwin	Reporter:	TSmort
Component:	aurorae	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	CONFIRMED ---
Severity:	minor	CC:	kde, kdedev, nate, xaver.hugl
Priority:	NOR
Version First Reported In:	6.3.5
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Screenshot of panel bug Screenshot of display settings

Description TSmort 2025-06-19 22:59:46 UTC

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SUMMARY


STEPS TO REPRODUCE
1. set your window decorations to something other than breeze (I've tested Layan, Edna, Otto, MoeDark, Apus, and Utterly-Round-Dark and all seem to have this problem)
2. edit your currently selected window decorations and set size to large (Utterly-Round-Dark has this issue on normal size)
3. take a window and fullscreen it. if it is already fullscreen un-fullscreen it and then re-fullscreen it

OBSERVED RESULT
there is a small (~ 1px) gap at the bottom of the window

EXPECTED RESULT
window is flush with bottom of screen or panel (or whatever else)

SOFTWARE/OS VERSIONS
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Arch
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.15.0
Qt Version: 6.9.1

ADDITIONAL INFORMATION
Unsure if this is a plasma bug or an issue with the community window decorations but it happens on quite a few window decorations and happens at the bottom of the window.

Comment 1 TraceyC 2025-06-24 17:41:04 UTC

I tested this on git-master with the Scratchy global theme and window style, following the steps in the report
I used Kate (native app) and Firefox windows, on a screen with a bottom panel and one without
Also tested with Layan, and with the Huge setting

I'm not able to reproduce on git-master or with a Fedora 42 VM with Plasma 6.4.0

Can you try to reproduce when your system updates to 6.4.0? Thanks!

Comment 2 TSmort 2025-06-25 02:13:18 UTC

(In reply to TraceyC from comment #1)
> I tested this on git-master with the Scratchy global theme and window style,
> following the steps in the report
> I used Kate (native app) and Firefox windows, on a screen with a bottom
> panel and one without
> Also tested with Layan, and with the Huge setting
> 
> I'm not able to reproduce on git-master or with a Fedora 42 VM with Plasma
> 6.4.0
> 
> Can you try to reproduce when your system updates to 6.4.0? Thanks!

having just upgraded to plasma 6.4, I can confirm that it still happens. My screen is 3:2. Could that have something to do with it?

Comment 3 TraceyC 2025-06-25 17:42:29 UTC

(In reply to TSmort from comment #2)
> having just upgraded to plasma 6.4, I can confirm that it still happens. My
> screen is 3:2. Could that have something to do with it?

I re-tested on a Fedora 42 VM with the display set to 3:2 and still couldn't reproduce.
My git-master systems don't offer 3:2 resolutions.

Is this your display's native resolution?

Also, can I ask you for a screenshot of Settings -> Display Configuration as well as a screenshot of your display showing the bug? Thanks.

Comment 4 TSmort 2025-06-25 20:22:38 UTC

(In reply to TraceyC from comment #3)
> (In reply to TSmort from comment #2)
> > having just upgraded to plasma 6.4, I can confirm that it still happens. My
> > screen is 3:2. Could that have something to do with it?
> 
> I re-tested on a Fedora 42 VM with the display set to 3:2 and still couldn't
> reproduce.
> My git-master systems don't offer 3:2 resolutions.
> 
> Is this your display's native resolution?
> 
> Also, can I ask you for a screenshot of Settings -> Display Configuration as
> well as a screenshot of your display showing the bug? Thanks.

This is my display's native resolution.
Display configuration screenshot: https://imgur.com/a/g7rNA7n
Screenshot of the bottom of my screen, at the top of my bottom panel: https://imgur.com/a/cADi7qh

Comment 5 TraceyC 2025-06-26 16:41:57 UTC

Thanks for the details. I'm attaching the screenshots to this report, so they stay with it and aren't at risk of being lost.

I do see the 1 px gap next to the panel in the screenshot. I suspect this is only seen with specific resolutions @ 135% or specific scaling.

I see the resolution in use is 2556x1504 @ 135%
I don't have that exact resolution available, but I did test with  135% scaling on different resolutions, on Fedora 42 and git-master
I'm still not able to reproduce. 

I do see a pixel of space underneath the bottom panel on Fedora with 2048 x 1152 (16:9) @135% but not 100%. This may or may not be related.

I'll leave this open so that people with different hardware available can try to reproduce.

Comment 6 TraceyC 2025-06-26 16:43:07 UTC

Created attachment 182694 [details]
Screenshot of panel bug

Comment 7 TraceyC 2025-06-26 16:43:26 UTC

Created attachment 182695 [details]
Screenshot of display settings

Comment 8 Zamundaaa 2025-06-27 21:09:16 UTC

Aurorae doesn't yet support fractional scaling completely issue free because of limitations in Qt APIs. It's unfortunately not super likely this will be fixed soon, but let's keep this around to track the problem.