SUMMARY In certain parts of Plasma, the Touchpad scroll direction setting is reversed when running a Plasma Wayland Session with Qt 5.14.x. This bug started for me in Plasma 5.17 when Manjaro & Arch updated to Qt 5.14. It still persists in Plasma 5.18 with Qt 5.14.1. Most apps respect the setting, but scrolling direction is reversed in the System Settings app, the Application Launcher, and the wifi networks list in the plasma-nm taskbar applet. [Scrolling in other areas may also be affected; these are the only ones I've noticed.] STEPS TO REPRODUCE 1. Open a Plasma Wayland Session with Qt 5.14.x. 2. In System Setttings, Input Devices, Touchpad: Choose your preference for "Invert Scroll Direction (Natural Scrolling)". 3. Attempt to scroll using the touchpad in the list of System Settings modules, the application launcher, or the wifi networks in the plasma-nm taskbar applet. OBSERVED RESULT The scrolling direction is opposite of the setting. EXPECTED RESULT The scrolling direction is the same as the setting. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: Linux 5.5.3-2-MANJARO (available in About System) KDE Plasma Version: 5.17.x and 5.18 KDE Frameworks Version: 5.65 through 5.67 Qt Version: 5.14 and 5.14.1 ADDITIONAL INFORMATION The bug is not present in Kubuntu 19.10 [with Plasma 5.17] or 20.04-nightly [with Plasma 5.18] because they build against Qt 5.12.x.
I can confirm this as well. I logged in to Wayland, opened System Settings and the scrolling (using touchpad) wasn't inverted, although it is inverted elsewhere - just the way I set it. Operating System: Manjaro Linux KDE Plasma Version: 5.18.0 KDE Frameworks Version: 5.67.0 Qt Version: 5.14.1 Kernel Version: 5.5.3-2-MANJARO OS Type: 64-bit Processors: 8 × Intel® Core™ i7-6700HQ CPU @ 2.60GHz Memory: 7,6 GiB
I found the earlier submission for this bug so this is a duplicate but I don't know how to mark it properly. https://bugs.kde.org/show_bug.cgi?id=417604 ALso, your report is of much better quality and more spot on, but I'm afraid you will have to copy/paste it to the previous report. Additionally, in the previous report it mentions apps that don't show this bug, at least for me and you didn't mention them, like Firefox. Scrolling on FF was fine (reverted) on Wayland.
*** This bug has been marked as a duplicate of bug 417604 ***