A popover shown from the Spotlight menu is stuck on the screen How do I get rid of it? It doesn't show up on task manager. It isn't dead, it responds to the  mouse wheel and scrolls up and down.

Screen shot below...
The process "QuickLook UI Helper" normally quits automatically after Spotlight is closed, but if it doesn't:


Open Activity Monitor
Find QuickLook UI Helper
Quit it (x button in the toolbar)