Bug 466127

Summary: Tiling configuration works erratically on cloned screens
Product: [Plasma] kwin Reporter: Michal Ziabkowski <mziab>
Component: Custom TilingAssignee: KWin default assignee <kwin-bugs-null>
Status: CONFIRMED ---    
Severity: normal CC: karl, nate, notmart, postix
Priority: NOR    
Version First Reported In: 6.2.3   
Target Milestone: ---   
Platform: Gentoo Packages   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Michal Ziabkowski 2023-02-20 09:48:59 UTC 
SUMMARY

I have two screens - a monitor (the primary screen) and a TV (which clones the primary screen). When I change the splits in tiling settings dialog, they seem to be changed not for the primary screen, but the other one. The end result is that the config changes don't apply. What I mean by this is that when I drag a window holding Shift, the new splits I've just added aren't there.

Looking looking at kwinrc, I have two tiling sections for each screen:
[Tiling][112a321c-1187-5b40-909d-f3bcef9080fa] - which seems to be TV
[Tiling][8e33597a-6e65-5852-ba3f-f97b7fd8a401] - which is the monitor (primary screen)

When changing the settings, they get applied to the first section (the TV), although it's not the primary screen. If I copy the tile settings to the second section (the monitor) and restart kwin, the new splits appear as intended.

Additionally, the config dialog doesn't seem to update. It only shows changes after I restart kwin. This might also be related to the issue of settings being applied to the wrong screen.

STEPS TO REPRODUCE
1. Set up a primary screen and a cloned screen
2. Open the tiling config dialog
3. Add new splits

OBSERVED RESULT
Splits aren't added for the primary screen, but the cloned one

EXPECTED RESULT
The config dialog shows the current (primary) screen and changes are applied to it

SOFTWARE/OS VERSIONS
Operating System: Gentoo Linux 2.13
KDE Plasma Version: 5.27.0
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8
Kernel Version: 6.1.10-gentoo (64-bit)
Graphics Platform: X11
Processors: 12 × AMD Ryzen 5 3600 6-Core Processor
Memory: 23.4 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 1650/PCIe/SSE2
Comment 1 Karl Ove Hufthammer 2023-03-05 12:10:33 UTC 
I think I’m having the same problem. Whenever I try to make any changes in the tiling layout editor, e.g., by dragging a split or clicking on any of the padding buttons, *nothing* seems to happen. The config dialog doesn’t update.

I too have two screens, a monitor (almost always powered off) and a TV. I don’t have the screens configured as clones, but they instead positioned so that they perfectly overlap, which has the same effect.
Comment 2 Karl Ove Hufthammer 2023-03-05 12:11:50 UTC 
BTW, I’m seeing this bug on Plasma 5.27.2:

Operating System: openSUSE Tumbleweed 20230303
KDE Plasma Version: 5.27.2
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8
Kernel Version: 6.2.1-1-default (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i5-2500 CPU @ 3.30GHz
Memory: 15.6 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 1060 3GB/PCIe/SSE2
Manufacturer: MSI
Product Name: MS-7673
System Version: 1.0
Comment 3 Michal Ziabkowski 2024-10-17 20:08:01 UTC 
Still present in Plasma 6.2.1 with the same symptoms. Clicking the tiling config elements, dragging the panes around etc. seems to do nothing at all.
Comment 4 Michal Ziabkowski 2025-02-09 14:31:23 UTC 
I've since switched to the Wayland session. Now the tiling configuration works... sometimes. It will work on one boot and then stop working on another. This seems like a race condition somewhere.  On boots where it doesn't work properly, restarting plasmashell doesn't help. Maybe this could be worked around by delaying the start of one of the services using a systemd override.

On a related note, on boots where the tiling config works, another multi-screen issue with the Present Windows effect I've been having also fixes itself. So I think the root cause for both might be the same - #481222