Can't change the model's background color for DS on Ubuntu 14.04

Hi,
I cannot change the background color of the model.. I cannot find from where do to it. Usually when I used to run DS in windows, I could put the words "background color" in the search box of the Options tab and it would just pop up, but even doing this in the DS for Ubuntu doesn't work, I mean it doesn't encounter the place where this parameter can be modified
Any ideas of how I can do it?