Created attachment 156406 [details] Demonstration of the issue SUMMARY *** NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols. See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports *** STEPS TO REPRODUCE Launched Firefox with MOZ_ENABLE_WAYLAND=1 then attempted to use middle-mouse click after enabling general.autoScroll in about:config. OBSERVED RESULT Autoscroll works, however the icon for it appears about 300px below the cursor and is unable to go above a certain height on the main screen. On the secondary screen, the icon still appears at the same distance below the cursor, however it is not limited to (roughly) the bottom half of the screen. EXPECTED RESULT Autoscroll icon should appear directly under the cursor after using middle-mouse click. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: Arch, KDE Plasma 5.27 (available in About System) KDE Plasma Version: 5.27 KDE Frameworks Version: 5.103.0 Qt Version: 5.15.8 ADDITIONAL INFORMATION Was an issue prior to 5.27. I had hoped the new multi-monitor support would resolve the issue, but it unfortunately has not.
My second monitor is vertical, so it expands above and below my primary monitor. I found that if I move my primary monitor up or down in Display Configuration, the cut-off for autoscroll moves as well. In this way, if I set my primary monitor to be top-aligned with my secondary monitor, then autoscroll behaves properly. This doesn't resolve the issue however, since in reality my primary monitor is not top aligned with my secondary monitor and it shouldn't have to be for the autoscroll icon to appear in the correct location.
Can reproduce.
The autoscroll icon is painted by Firefox itself, so this is almost certainly a bug in Firefox. Please report this to Mozilla
It's been reported here for anyone who would like to follow it or add their report: https://bugzilla.mozilla.org/show_bug.cgi?id=1817387