I use my laptop either with two external screens connected to a docking station while the laptop screen is disabled (lid is closed) or only on laptop screen.

I have panel on both screens (and of course when using only the laptop screen) with a task manager widget. The task managers are set to display apps only from current screen, desktop and activity.

After I remove the computer from the docking (thus the external screens are disconnected) no apps are shows by the remaining task manager. However, if I disable the show apps from current screen filter, the apps are shown again. Enabling the filter hides them again.

It seems, that the apps are somehow stuck on the disconnected screen, at least for task manager, because otherwise the are perfectly shown.

This bug appeared in 5.8.5 as I remember. Maybe it is connected to bug 371734 and it's fix. Maybe it is a multi screen issue also.

My system is Opensuse Tumbleweed, Plasma 5.8.5, Frameworks 5.29.0, Qt 5.7.1, kernel 4.9.3 64bit