Comment 42 for bug 521492

Can confirm that this bug still appears in Ubuntu 12.04.

Have noticed that using Advanced Settings (gnome-tweak-tool) to set "Have file manager handle the desktop" to Off reverts control of the desktop background to Compiz, so if you have a background set in CompizConfig Settings Manager's Wallpaper plugin it displays in the correct manner, i.e. tiled from the top left corner across both screens. However, doing so also disables icons and the right-click menu on the desktop. Given this, is it possible that it's an issue with Nautilus?