[ubuntu] No access to desktop in Unity for 16.04

Yes. Top panel is there and working fine. I had launcher on left, but changed it to go to bottom. I have Libre office and File Manager icons. I have resized the icons though.

But when I try to change the wallpaper and right click on desktop, I didn't get any menu. I was not able to change background as well. I even went to settings and tried changing wallpaper there. No effect on default wallpaper on desktop. I updated while I was within Gnome since I couldn't bring back Unity before update. I reinstalled Unity and want to use it now.

Thanks. I will try those commands.

PS : I use Radeon drivers. I had to choose alteative option in " Additional Drivers ". Could that be an issue ?