Bug 507510

Summary:	New application windows are created off-set from the position requested via KWin settings.
Product:	[Plasma] kwin	Reporter:	Chiitoo <chiitoo>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	kdedev
Priority:	NOR
Version First Reported In:	6.3.5
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Chiitoo 2025-07-26 13:42:09 UTC

SUMMARY

When the KWin X11 window placement setting is set to, for example, centred or top-left, opening new windows opens them slightly towards the bottom-right, instead of the same position always.

STEPS TO REPRODUCE
1. Set 'window behaviour' / 'window placement' to 'centred'.
2. Open a video file using 'mpv'.
3. Open another video file using 'mpv'.
4. Observe the second window open up not-centred.

Opening something like, say, KWrite, regardless of its window size, and then a video file with mpv has the same effect.

OBSERVED RESULT

New windows are opened in an unexpected position.

EXPECTED RESULT

New windows open up at the expected position.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: Gentoo Linux (Not a full Plasma install, but using KWin with LXQt.)
KDE Plasma Version: 6.4.3
KDE Frameworks Version: 6.16.0
Qt Version: 6.10 (838d543cd2adddce6419faa91647192653d71088)

ADDITIONAL INFORMATION

Wayland behaviour not tested at all.

Comment 1 Bug Janitor Service 2025-07-26 14:33:38 UTC

Thank you for the bug report!

However Plasma 6.3.5 no longer receives updates or maintenance from KDE; active versions are 6.4 or newer. Please upgrade to an active version as soon as your distribution makes it available to you. Plasma is a fast-moving project, and bugs in one version are often fixed in the next one.

If you need help with Plasma 6.3.5, please contact your distribution, who bears the responsibility of providing help for older releases that are no longer receiving updates from KDE.

If you can reproduce the issue after upgrading to an active version, feel free to re-open this bug report.

Comment 2 Chiitoo 2025-07-26 14:59:54 UTC

I suppose the "version first reported in" is a bit confusing to me here.

Re-opening as this is happening with a current release still.

Comment 3 TraceyC 2025-07-28 19:51:35 UTC

Thanks for the report. My apologies for the bug being auto-closed. You filled in the right information, the bot did the wrong thing with it.

I'm able to confirm the behavior you're seeing on Plasma 6.4.3. It looks intentional, so that the new windows can be seen by the user and it doesn't look like new windows aren't opening.

There's another way you can get the behavior you want.
If you use the window's More Actions-> Window Settings -> Position - Apply initially to (0,0), the window is always opened at that position. You can use other position numbers as well. Would that work for you?

Comment 4 Chiitoo 2025-07-29 12:06:26 UTC

Indeed, I figured it looks potentially intentional though not really fitting for me, and yeah, applying an initial position works, and helps with the issue that seems to have started with 6.10, affecting Qt applications (https://bugs.kde.org/show_bug.cgi?id=507507).

Thank you!

Comment 5 TraceyC 2025-07-29 19:50:03 UTC

You're welcome! I'm glad you've found a setting that works for your use.

Unfortunately, I don't have a system with Qt 6.10 to test the other report, but someone else will get to it.

Comment 6 Chiitoo 2025-07-29 22:46:52 UTC

Yeah, Qt 6.10 isn't quite out yet (well, beta2 is out by now I suppose), but figured reporting early.

Also setting the initial position will of course be a bit tricky with windows that might be of different sizes (like a video or images), if expecting them to be centred but I can probably figure out with something more for it (could also force the initial size, though maybe that's not optimal either...).