No KDE Plasma bar in desktop mode
The bottom bar (where the start menu button is) on one of the output devices is missing. The appearance depends on the "main" setting, which is under the "on" setting in the "screen and monitor" section. If the TV is the main device, the bar appears on the monitor. If the main device is the monitor - vice versa. In the monitor only, TV only or mirroring mode, the bar disappears altogether.