Background changes only for Gnome, not Unity

[S. Patrikios]

Havee file manager handle the desktop: Off (if On, a white background is shown, no matter what).
The desktop behaviour is erratic to say the least.
Should you select any picture fpr the background, that picture shows in Gnome desktop, but not in Unity, which remains black, unless file manager handles the desktop, where it is white!
Unity leaves a shadow in place though hidden.

lsb_release -rd
Description: Ubuntu 13.04
Release: 13.04
apt-cache policy lightdm
lightdm:
  Installed: 1.6.0-0ubuntu2.1
  Candidate: 1.6.0-0ubuntu2.1
  Version table:
 *** 1.6.0-0ubuntu2.1 0
        500 http://gr.archive.ubuntu.com/ubuntu/ raring-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1.6.0-0ubuntu2 0
        500 http://gr.archive.ubuntu.com/ubuntu/ raring/main amd64 Packages

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1176344/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Fabio Marconi (fabiomarconi)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This bug did not have a package associated with it, which is important for ensuring that it gets looked at by the proper developers. You can learn more about finding the right package at https://wiki.ubuntu.com/Bugs/FindRightPackage . I have classified this bug as a bug in unity.

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://help.ubuntu.com/community/ReportingBugs.