I have a laptop that I connect to an external monitor. I want the primary screen always to be on the Laptop (and for this reason the laptop is placed on the left of the external monitor due to this bug: https://bugs.kde.org/show_bug.cgi?id=318430) and have a panel with a task manager plasmoid only to appear whenever I connect the external monitor. When I disconnect it, I want this panel to disappear. Is this possible?

If I create a panel and put it in the external monitor it is working fine, but when I disconnect the external monitor the panel will move to the primary monitor. That's something I don't want. Moreover, the moved panel will be on top, covering my primary panel!

This has been requested before - unfortunately to the best of my knowledge this is not possible. I would suggest filing a feature request at bugs.kde.org. I'm not sure exactly how the Plasma developers would want to handle this, as it is quite a tricky situation unfortunately.

Also see viewtopic.php?f=67&t=110721&p=262718&

Thanks! Just filed a bug (wishlist) here: https://bugs.kde.org/show_bug.cgi?id=319410