STEPS TO REPRODUCE 1. right click on desktop, select "Configure desktop" 2. click "Mouse actions" section in the left side 3. set "Applications launcher" as action for the middle button 4. click "Apply" button 5. select another action for the middle button (now you can not apply the new setting because "Apply" button is disabled) 6. close and reopen "Configure desktop" window > "Mouse actions" section OBSERVED RESULT "right button" and "left button" disappeared from "Mouse actions" section. You only can configure actions for the "Middle button". Toolbox (hamburger menu in the upper right corner of the screen) does not work, mouse clicks have no effect. EXPECTED RESULT "Mouse actions" are still configurable for left and right buttons and toolbox is still working. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.15.0 KDE Frameworks Version: 5.55.0 Qt Version: 5.12.1 ADDITIONAL INFORMATION I can't reproduce on neon dev unstable.
https://cgit.kde.org/plasma-desktop.git/commit/?id=42fb1de1b3fae6b121ef9c1651728a258f4e17ce