Ubuntu – Right-clicking on the Unity desktop does nothing – ideas

I was reading today the latest Canonical design blog post where I was kind of surprised that one should be able to right click on the desktop to change the wallpaper. I am running the most updated version of natty and have the latest unity package installed (3.8.10) but right clicking on the desktop brings nothing on my machine. On the other hand, when I right click on any launcher icon I do get a quick list, so I know it's not a problem with my mouse or something. Is this a known bug?

I tried to kill Nautilus as Nathan suggested using Alt+F2 and then killall nautilus. Just to be sure, I then opened a terminal window and typed the same command again. Got the response nautilus: no process found (I figured that my first try to kill nautilus worked then. Just to be on the safe side, I clicked the "Home" icon on my launcher to start Nautilus, and then killed it again (same command). Still nothing happened.

Following some of the comments below, I should specify that I do have ubuntu-desktop installed (and updated version 1.220) and nautilus is indeed installed (Version: 1:2.32.2.1-0ubuntu13). (Used to have nautilus from the elementary PPA, but removed it following the comments below – still no luck).