Created attachment 103664 [details] Screenshot of one of the screens and half of switch user menu It happens in two monitor setup and monitors outputs are separated (left - right). When you try to switch user one half of switch user window / menu is on the one screen and second half is on another screen. It very annoying when one of that screens is your tv which is far from the other screen so it is hard to see them both at the same time (it is hard to see anything because of the distance).
In Plasma 5.9 the user switcher greeter has been split into a separate binary like the logout greeter that spawns a window for each screen.