Unity launcher stays behind windows
I have been having a problem with Unity launcher recently. Launcher stay behind my windows and I can't bring it to the front of my windows! 
As you can see, the Nautilus window is in front of the launcher menu and the menus are totally inaccessible when the window is maximized.
Open your terminal by pressing Ctrl + Alt + T and type this following to solve this problem:
unity&disown
Hit Enter to generating this commands, you'll see screen will flick a few times, just don't panic ! Wait for a few second and everything will back to normal again