I’ve just updated my system to use plasma 5.20 and the “System” options within the “Leave” tab of the application launcher applet are missing. That includes the restart/shutdown/sleep/hibernate options.
I created and logged in as a new user, the options are there. So it seems to be broken only on my profile. The “Offer shutdown options” is selected in the system settings, and my user is in the power group.
If you ever figure out how did you do it, could you post here? I have long wanted to edit the leave menu, but found the directions for hibernate removal a bit daunting, but perhaps you can try to undo them in reverse sequence.
I’ve narrowed the problem down to latte-dock. If I add the widget to a normal plasma panel or even the desktop, the options are displayed. They are only missing when the applet is added to a latte-dock panel.
Unfortunately I added a latte dock to the new user and it exhibited exactly the same behavior. The power options are there after adding the applet, but disappear after a reboot. In this case creating a new profile won’t fix it. Hopefully it’ll get fixed upstream. For now I’ve simply moved the applet to a non-latte panel.