When running UE4Editor and so far one game on my system (Shadows Of Mordor) causes the plasma panel to stop redrawing itself. The clock, Task Manager etc, seem to show a static image of from the first time that application is launched in a session. The panel still responds to mouse and keyboard input. The Plasma panel responds normally after the offending application is closed. These symptoms show up on both my desktop (i7 + nVidia 460,580 and 960 i have upgraded graphics cards twice since first encountering this issue) and my laptop (i7 + nVidia 870m) using both Kubuntu (lets say 16.04 onwards) and Manjaro Testing. Quite a number of different driver revisions have been used over that time but the current one is 375.26. To test build UE4 https://wiki.unrealengine.com/Building_On_Linux or via the packaging system on Arch and Run UE4Editor.
*** This bug has been marked as a duplicate of bug 353983 ***