Bug 514460

Summary: Windows bleed 1 pixel to the left of where it should be
Product: [Plasma] kwin Reporter: pg_tips <pg_forums>
Component: multi-screenAssignee: KWin default assignee <kwin-bugs-null>
Status: REPORTED ---    
Severity: minor CC: nate
Priority: NOR Keywords: multiscreen
Version First Reported In: 6.5.4   
Target Milestone: ---   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description pg_tips 2026-01-11 16:03:45 UTC 
SUMMARY
On a multi-monitor setup, a window whose left edge should be exactly aligned with the edge of a screen bleeds 1 pixel leftward, intruding into the adjacent display.

STEPS TO REPRODUCE
1. Have two 1920*1080 screens, arranged horizontally next to each other.
2. In Plasma, open a non-maximised application (let’s say Dolphin)
3. Half-tile the window to occupy the left half of the right-hand monitor. Or alternatively, use kdotool windowmove to position it at (1920, 0) - the issue isn’t specific to using the tiling feature.

OBSERVED RESULT
A 1-pixel wide vertical strip of the window appears at the right-hand edge of the left-hand screen.

EXPECTED RESULT
The left-hand edge of the window occupies precisely the left-hand edge of the right-hand screen, with no bleed into the left-hand screen.

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 43
KDE Plasma Version: 6.5.4
KDE Frameworks Version: 6.22.0
Qt Version: 6.10.1
Kernel Version: 6.18.4-200.fc43.x86_64 (64-bit)
Graphics Platform: Wayland

ADDITIONAL INFORMATION
I'm not positive that Plasma 6.5.4 specifically introduced this, but it's a pretty recent issue. I think it's appeared only in the last ~2 months.
Comment 1 pg_tips 2026-01-11 16:04:21 UTC 
I should add, my theme is the stock "Fedora" theme, which is very similar to standard Breeze.
Comment 2 pg_tips 2026-01-13 16:07:23 UTC 
I think this isn't specific to multi-monitor setups (though it's more visually noticeable in the multi-monitor configuration I described).

For example, in default Breeze (therefore no window borders):

1. Set the wallpaper to solid red (so the effect is easy to see)
2. Open a window
3. Use kdotool to reposition the window to x=1, y=0

Expected result is a 1-pixel wide strip of red (from the wallpaper) at x=0.

Instead, the x=0 strip is occupied by the left-hand edge of the window and you can't see any red.