Bug 502806

Summary:	Windows aren’t moved and restored properly when (un-) plugging USB-C dock with a HDMI monitor plugged to it
Product:	[Plasma] kwin	Reporter:	ariasuni <aria>
Component:	multi-screen	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	nate
Priority:	NOR	Keywords:	multiscreen
Version First Reported In:	6.3.4
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description ariasuni 2025-04-14 19:00:18 UTC

SUMMARY
I use Plasma with two monitor: the builtin one from my laptop, and an external monitor, plugged via HDMI to a USB-C dock.

KWin don’t behave correctly with regards to moving windows and sizing when plugging and unplugging the dock.

STEPS TO REPRODUCE
1. Two screens, with one plugged with HDMI through an USB-C dock
2. Two Firefox windows (and other maximized windows)
3. Unplug the USB-C dock
4. Plug back the USB-C dock

OBSERVED RESULT
When unplugging the USB-C dock, the Firefox window (it’s fine for other applications) displayed on the external monitor stay stuck on the ghost screen and I can’t move it back to the builtin screen (tried shortcuts to move windows to other screens, using actions in the contextual menu of the panel task manager). Only way to access the stuck windows I found is to plug back a monitor.

When plugging the USB-C dock back, some maximized windows are restored with the size covering the entire screen, so they go under the (non-floating) panel, as if the panel wasn’t there when the windows were moved back to the external screen.

EXPECTED RESULT
When unplugging the USB-C dock, the Firefox window is moved to the builtin screen.
When plugging the USB-C dock back, the maximized windows are restored to the correct size.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.12.0
Qt Version: 6.9.0
Kernel Version: 6.14.2-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 8 × AMD Ryzen 7 3700U with Radeon Vega Mobile Gfx
Memory: 13.5 Gio of RAM
Graphics Processor: AMD Radeon Vega 10 Graphics
Manufacturer: LENOVO
Product Name: 20NFCTO1WW
System Version: ThinkPad E595

ADDITIONAL INFORMATION
The USB-C dock I’m using is a Thinkpad (40AY) (https://www.lenovo.com/fr/fr/p/accessories-and-software/docking/docking-usb-docks/40ay0090eu).

Comment 1 Nate Graham 2025-04-18 16:48:58 UTC

Does it happen for all windows tested? Or only some?

Does matter if the windows on the external screen are windowed, maximized, quick-tiled, custom-tiled, fullscreen, etc?

Anything you could to do find a pattern here would be very helpful.

Comment 2 ariasuni 2025-04-21 15:27:43 UTC

I filmed the bug:
https://www.youtube.com/watch?v=d1JOpg19xkc

Interestingly, this time after trying to move the Dolphin window, when I replugged the dock, the Dolphin window appeared on the builtin monitor (instead of the external one) and was very tiny (???), but it’s the first time this happens to me.

Comment 3 Nate Graham 2025-05-28 16:02:36 UTC


*** This bug has been marked as a duplicate of bug 479694 ***