There are small jumps (usually down) when scrolling main list (up or down doesn't matter). Well noted when scrolling with touchpad, it's very hard to scroll to the list top with touchpad as that jumps happen almost constantly. When mouse scroll is used jumps are present but not so badly. But mouse scroll is too slow (about 15-20px per scroll), but that's unrelated bug, I saw bugreport somewhere. Reproduce: 1. Open systemsettings. 2. Scroll main list using touchpad to the list bottom. 3. Scroll main list to list top. Expected results: Both 2nd and 3rd step work fine. Actual results: 2nd step works but scrolling is jagged. 3rd step is hard to achieve as scroll area jumps down. Scroll (using touchpad) in other QML dialogs (like plasma desktop settings) works fine.
Same issue here when scrolling with Elan touchpad, making it nearly impossible to normally scroll the system settings categories in the left pane.
I've found that reason is horizontal scroll. If horizontal scroll is off, it looks fine. Scrollbar still looks like jumping slightly sometimes in counter direction, but content is scrolled rather smoothly (maybe just visual problem). But horizontal scroll (both left and right) scrolls to list bottom.
To clarify, I'm using two fingers scroll which provide both vertical and horizontal scroll, so even if you'll scroll up/down there are small left/right scrolls which leads to scroll to list bottom.
I can confirm that horizontal scroll is the issue with touchpad. A mouse scrollwheel works just fine.
Ok, It seems it was fixed and fine for quite some time. So I'm closing this.