Bug 510290

Summary: when using Podman with X11 forwarding, quickly moving the mouse horizontally across the top menu bar in any QT application to rapidly switch between different dropdown menus triggers UI freezing.
Product: [Plasma] kwin Reporter: 5kaslclz2 <5kaslclz2>
Component: xwaylandAssignee: KWin default assignee <kwin-bugs-null>
Status: REPORTED ---    
Severity: normal CC: kde, xaver.hugl
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description 5kaslclz2@mozmail.com 2025-10-06 07:58:10 UTC
SUMMARY
when using Podman with X11 forwarding, quickly moving the mouse horizontally across the top menu bar in any QT application to rapidly switch between different dropdown menus triggers UI freezing.

STEPS TO REPRODUCE
1.
 Create a container image with any QT application:
```dockerfile
FROM docker.io/debian:latest

RUN apt-get update && \
    apt-get install -y wireshark && \
    apt-get autoclean
```
2. 
Run the QT application with X11 forwarding
```sh
podman build -t test .  
podman run -it --rm \
-v /tmp/.X11-unix/X1:/tmp/.X11-unix/X1:rw \
-v $XAUTHORITY:/root/.Xauthority \
-e DISPLAY=$DISPLAY \
localhost/test wireshark
```
3. 
Quickly swiping the mouse horizontally back and forth across the top menu bar to rapidly switch between different dropdown menus 

OBSERVED RESULT
UI freezes for several seconds  before recovering responsiveness.
journalctl -f
 arch kwin_wayland[1367]: kwin_wayland_drm: The main thread was hanging temporarily!

EXPECTED RESULT
no  UI freezing

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:  Arch Linux x86_64
KDE Plasma Version:  6.4.5
KDE Frameworks Version: 6.18.0
Qt Version:  5.15.17

ADDITIONAL INFORMATION
Successfully reproduced on both AMD RX6500 and  Intel Iris Xe
Comment 1 David Edmundson 2025-10-06 16:32:23 UTC
Does the mouse still move in this situation?
Comment 2 5kaslclz2@mozmail.com 2025-10-07 11:14:28 UTC
(In reply to David Edmundson from comment #1)
> Does the mouse still move in this situation?

The mouse freezes in the Wayland session, but it can move in the X11 session.
Comment 3 5kaslclz2@mozmail.com 2025-10-07 11:35:53 UTC
Enabling TUN mode in some proxy  software, such as  clash-verge-rev can temporarily resolve this issue.