Bug 437340

Summary: OverlaySheet: scrolling with thumb is weird and sometimes makes lists jump
Product: [Frameworks and Libraries] frameworks-kirigami Reporter: Matthew Cline <matt>
Component: generalAssignee: Marco Martin <notmart>
Status: RESOLVED DUPLICATE    
Severity: normal CC: nate, plasma-bugs
Priority: HI Keywords: usability
Version: 5.82.0   
Target Milestone: Not decided   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed In:

Description Matthew Cline 2021-05-19 07:30:45 UTC 
1. Go to System Settings > Regional Settings > Language
2. Select "Add languages"
3. Left click on the scroll thumb and slowly drag it down.
4. The list will eventually jump/stutter/flicker.
5. Stop and try to select and element by left clicking.  The list will jump again and nothing will be chosen.

Everything works fine if instead I scroll using the mouse wheel.

wayland-errors has multiple lines like this:

kwin_libinput: Libinput: event3  - Logitech USB Keyboard: client bug: event processing lagging behind by 15ms, your system is too slow

Also, I have the env var KWIN_TRIPLE_BUFFER set to 1, if that matters.
Comment 1 Nate Graham 2021-05-19 19:22:43 UTC 
This is caused by the wonky scrollbar behavior of the Kirigami.OverlaySheet component. It was really designed for touch or touchpad or wheel scrolling and not for people using the scrollbar. :)
Comment 2 Nate Graham 2021-12-02 19:32:07 UTC 

*** This bug has been marked as a duplicate of bug 438079 ***