I confirm this bug, and it really seems to be caused by nautilus. In fact, if you disable nautilus autostart (by removing the /etc/xdg/autostart/nautilus.desktop file), the desktop background will not be painted.
Then, if you start "nautilus -n" manually from a terminal, you'll see the desktop background being shifted a few pixels to the right, and then reverting back to the correct position. This happens also when metacity is not running, which seem to exclude a window manager bug. ** Changed in: nautilus (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/804435 Title: Wallpaper is loaded twice with different alignment by gnome-session and nautilus (Oneiric) To manage notifications about this bug go to: https://bugs.launchpad.net/unity-2d/+bug/804435/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs