Bug 474825

Summary: Dragging a window in Present Windows/Overview with both touchscreen and touchpad halts kwin
Product: [Plasma] kwin Reporter: unblended_icing552
Component: effects-window-managementAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED FIXED    
Severity: crash CC: nate, unblended_icing552
Priority: NOR    
Version First Reported In: 5.27.8   
Target Milestone: ---   
Platform: openSUSE   
OS: Linux   
Latest Commit: Version Fixed In: 6.0
Sentry Crash Report:

Description unblended_icing552 2023-09-24 00:48:47 UTC 
SUMMARY
In Present Windows/Overview, if you drag a window using both touchscreen and touchpad (maybe mouse also works), the window glitches and the whole interface is unresponsive. After a while the screen goes blank. Alt + Space won't open KRunner in this case.

A coredump doesn't generate and nothing shows up within KDE Crashed Processes Viewer, so a crash report isn't available. But the issue is reliably reproducible.

STEPS TO REPRODUCE
1. Use a laptop with touchscreen
2. Use KDE Plasma Wayland session
3. Open any window (openSUSE's Welcome page in my case)
4. Activate Present Windows effect
5. Drag that window using both touchscreen and touchpad

OBSERVED RESULT
The dragged window glitches, the whole interface is unresponsive. After a while the whole screen goes blank. Alt + Space doesn't open KRunner. TTY console is still accessible.

EXPECTED RESULT
The dragged window should follow either touchscreen input or touchpad input (given a stable priority), without halting the whole interface.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.10

ADDITIONAL INFORMATION
Wayland session.
Intel Graphics.
Microsoft Surface device.
Comment 1 Nate Graham 2023-09-25 18:13:17 UTC 
Can you attach a phone recording of what happens so we can be 100% clear that we understand the issue? Thanks!
Comment 2 unblended_icing552 2023-09-26 02:03:54 UTC 
KDE Bugs attachment has strict file size limit.

https://upload.disroot.org/r/U4E3naqq#5fro5OFTIY70YMDy/rZ6sEkfkwqdBjvfooDIj+eXlSk=

(expires in 30 days)
Comment 3 Nate Graham 2023-09-28 20:14:25 UTC 
Got it, thanks.

This was a bug that was just fixed for Plasma 6 with a total rewrite of the effects. I can confirm it works now.