I've just upgraded to Ubuntu 15.04 and first noticed that this problem has been resolved, but there are still some complications it seems.
When I ran Nautilus as root (using the command "gksu nautilus") I suddenly saw that the Unity Launcher background switched to the default background again.
What's worse, when I tried getting rid of it by entering terminal command "nautilus -q", I saw that my desktop background changed to default one.
I've just upgraded to Ubuntu 15.04 and first noticed that this problem has been resolved, but there are still some complications it seems.
When I ran Nautilus as root (using the command "gksu nautilus") I suddenly saw that the Unity Launcher background switched to the default background again.
What's worse, when I tried getting rid of it by entering terminal command "nautilus -q", I saw that my desktop background changed to default one.