For a while, I have been unable to add anything from the Application Launcher’s Leave section to Favorites. Anything else seems to work, but not Shutdown, Reboot, Logout etc. I have seen this behaviour in KDEneon and in kubuntu 18.04. Any ideas how to fix this?

Trying it out in PCLinuxOS with Plasma 5.12.4, I can get it to work when using the Application Menu, but not when using the Application Launcher (right-click on the launcher icon and select Alternatives to switch).

Seems to be a proper bug, then. I’m seeing the same in Sabayon 18.05 (Plasma 5.12.3) and Neptune.

Same problem in KDE Neon with plasmashell 5.12.5, I recieved an update today and I hope it can be fixed with this upgrade.

I received the plasmashell 5.13 upgrade and everything works fine. If you want to add leave options you have to change the Launcher application panel configuration with the right click on the start symbol.

Regards