Created attachment 104927 [details] Screenshot of multi-screen setup and panel pop-ups appearing in the wrong place. Hi, I have a laptop connected to an external monitor. When I invoke a panel widget it appears not adjacent to the panel as is the expected behaviour. Look at screenshot for more information. Stock Kubuntu 16.04 without any modifications.
*** Bug 378574 has been marked as a duplicate of this bug. ***
Plasma 5.5 is quite old, and there were many multi-screen fixes in newer versions. Please ask in a forum of your distribution how to update to Plasma 5.8 or newer.
I was experiencing that in past, but now it is no longer happening