Created attachment 104521 [details] Screenshot of the issue. When you right click on an application in the task manager it opens the options menu, when you right click multiple times without closing the initial menu, it spawns multiple menus on top of eachother. When you right click on one application and without closing the menu, right click on another application it also opens multiple menus Screenshot attached. Notice the shadow on the KInfoCenter menu, tens of menus are spawned there
KWin doesn't know how to deal with popup windows (ie. close on clicking outside) yet
*** This bug has been marked as a duplicate of bug 366609 ***