Bug 453560 - Windows not always snap on resize
Summary: Windows not always snap on resize
Status: CONFIRMED
Alias: None
Product: kwin
Classification: Plasma
Component: multi-screen (other bugs)
Version First Reported In: git master
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-05-09 06:04 UTC by gudvinr+kde
Modified: 2025-04-27 23:15 UTC (History)
2 users (show)

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Description gudvinr+kde 2022-05-09 06:04:00 UTC
SUMMARY

Sometimes, windows don't snap to window edges on resize.
I have this monitor setup:
- left 3840x2160 + right 1440x2560

I am not sure whether or not it works with X11 but I don't feel like trying because switching between Wayland and X1 messes my desktop layout every time I do that. But I don't remember it not working because it is what I do relatively often and I started to notice that after switching to Wayland.

It doesn't always happen and it doesn't happen with all windows:
- MPV window doesn't snap to the right side of the right monitor, to the bottom of both and to the top of both. Both with and without borders. But it does snap to the edge between monitors and to the left side of the left monitor.
- Discord window doesn't snap to the right and bottom when minimized but snaps okay to the top, to the left, to the edge between monitors and to the right when maximized vertically. Same with Firefox

STEPS TO REPRODUCE
1. Open window
2. Try to resize

OBSERVED RESULT
Window snaps to all screen edges

EXPECTED RESULT
Windows sometimes don't snap

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.24.5
KDE Frameworks Version: 5.93.0
Qt Version: 5.15.3
Graphics Platform: Wayland
Graphics Processor: AMD VEGAM
Comment 1 Lenzoid 2025-04-26 18:27:08 UTC
Thank you for your bug report. I'm most recent KDE version 6.4 dev and it seems windows generally do not snap on resizing, only on moving, so you should use move the window first, then resize. Hope that makes sense.

I believe since KDE 6 we now have a tiling feature, default hotkey is Meta (Win-Key) + T. This also might help you in arranging your windows.

I'm inclined to flag this as Resolved (Intentional).
Comment 2 gudvinr+kde 2025-04-27 08:58:58 UTC
(In reply to Lenzoid from comment #1)
> I'm inclined to flag this as Resolved (Intentional).

In all honesty, that's not how one should bring number of bugs done.

How is this intended? It just means snapping is broken because it works sometimes but not in all cases where you expect.

> you should use move the window first, then resize

That's just a dumb workaround and you must (not should) use it only because snapping is broken. That's just ruining UX by wasting your time.

> I believe since KDE 6 we now have a tiling feature

It is subpar tiling for now. I hope it will be better in the future but in any case, that's also workaround and not a solution.
Comment 3 Lenzoid 2025-04-27 13:06:19 UTC
Judging from what I see in the Settings > Window Behavior there are a bunch of snap settings but only for "Movement". So that is why it seems intentional to me. I'm only looking at most recent KDE and here there seems no snapping on resize at all. 

I will try and find a person of the dev or design team to comment on this, maybe we'll additionally make a feature request, independently of this bug report. 

I agree if it's an inconsistent behavior that does suggest a bug, but I don't have a KDE 5 version to test right now and while they do offer support for it, it's very difficult to go beyond the most basic of support.

See an explanation here https://discuss.kde.org/t/how-long-plasma-5-will-be-mantained/7276/6 

What version are you on right now?
Comment 4 Lenzoid 2025-04-27 16:22:00 UTC
Ok, testing around in a fresh user profile I think I have very similar issue in 6.4 dev wayland. I'll do some more testing as it's somewhat inconsistent behavior.
Comment 5 Lenzoid 2025-04-27 23:15:01 UTC
Steps to reproduce:

(In my video you'll see it working as expected on the left screen, and buggy on the right. It doesn't matter which screen is set as primary)
https://youtu.be/z2z6LK60CKg

- KDE Plasma 6.3.4 or 6.4 dev (git master) at two screens.
- Resize window up to top screen border, try on both screens. On one monitor you should notice that snap doesn't work, on the other it works fine. (You should see this on Wayland and X11)
- Try to resize to other edges of the screen, others are affected too.

Could reproduce this on both my machines, one with nvidia one with amdgpu, X11 and Wayland. X11 has had different borders not working but the top border was affected on both.

Bug doesn't appear with only one screen, so I'm moving this to multi-screen.