Comment 2 for bug 1115886

I couldn't replicate the problem of not being able to change the wallpaper, but toggling that setting causes problems with the fade animation of changing the wallpaper.

I opened dconf-editor, and it looks like the box was unchecked by default (even though in gnome-tweak-tool, "have file manager handle the desktop" is on). I checked it to enable it (org.gnome.desktop.background.show-desktop-icons) then changed the wallpaper and it worked as expected. When I toggled that setting off again I was still able to change the wallpaper but it didn't fade in between wallpapers, it was an abrupt change. It also disabled nautilus handling the desktop.