Bug 500098

Summary: Window Action Maximize/restore behaves weirdly when using a touchpad since Plasma 6.3
Product: [Plasma] kwin Reporter: David G. <tamale-kooky-nifty>
Component: effects-window-managementAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED FIXED    
Severity: minor CC: kde, nate
Priority: NOR    
Version First Reported In: 6.3.0   
Target Milestone: ---   
Platform: NixOS   
OS: Linux   
Latest Commit: Version Fixed/Implemented In: 6.4.0
Sentry Crash Report:
Attachments: Screen Recording of holding the Meta Key and scrolling up with the touchpad

Description David G. 2025-02-14 22:24:06 UTC
SUMMARY
Since Plasma 6.3, the Window Action "Maximize/restore" behaves weirdly when using a touchpad, especially when trying to maximize.

STEPS TO REPRODUCE
1. Use Wayland
2. Use a touchpad
3. Under Settings -> Window Management -> Window Behavior -> Window Actions, set "Mouse wheel" to "Maximize/restore"
4. Hover over a window that is not maximized
5. Hold the Meta key and scroll up (or down if Natural Scrolling is enabled)
6. Stop scrolling and release the Meta key

OBSERVED RESULT
When scrolling, the window jumps quickly between maximized and unmaximized.
After stopping scrolling and releasing the Meta key, the window is either maximized or unmaximized.

EXPECTED RESULT
The window should be maximized and not change its state while scrolling.

SOFTWARE/OS VERSIONS
Operating System: NixOS 25.05
KDE Plasma Version: 6.3.0
KDE Frameworks Version: 6.10.0
Qt Version: 6.8.2
Kernel Version: 6.13.2 (64-bit)
Graphics Platform: Wayland
Processors: 8 × 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
Memory: 31.1 GiB of RAM
Graphics Processor: Intel® Iris® Xe Graphics
Manufacturer: Framework
Product Name: Laptop
System Version: AA

ADDITIONAL INFORMATION
- It worked in Plasma 6.2.5
- It only happens on Wayland, X11 works as expected
- It also happens in the latest KDE Neon Unstable Edition Live Image (Plasma 6.3.80)
- It also happens on another Laptop using the KDE Neon Live Image
- A similar thing can be observed when using Mouse Wheel actions other than "Maximize/restore"
- Similar to https://bugs.kde.org/show_bug.cgi?id=476047
Comment 1 David G. 2025-02-14 22:36:53 UTC
Created attachment 178385 [details]
Screen Recording of holding the Meta Key and scrolling up with the touchpad
Comment 2 Vlad Zahorodnii 2025-02-19 11:06:06 UTC
6.2 has never had code to handle touchpad scrolling. https://invent.kde.org/plasma/kwin/-/blob/v6.2.5/src/input.cpp?ref_type=tags#L1780
Comment 3 David G. 2025-06-23 12:16:01 UTC
After updating from Plasma 6.3.5 to 6.4, I can confirm, it now works as it used to.
I don't know which commit fixed it but I am happy that I can use the Window Action reliably again.