disable desktop background in fedora 13 (LXDE)

[Ranjan Maitra]

Hi, 

I was wondering how one does it: I have been looking at the Preferences
-> Desktop but I can not find a way to have it take nothing as the
background. Previously, in F10,11,12, I recall that there was a button
somewhere which said no background. I can not find it here. 

Any help?

Many thanks!
Ranjan