[Chimera-users] molecular surface isolated to chain

Hello, I am trying to create a nice aesthetic model of a protein binding to DNA. When I show molecular surface, the program doesn't seem to be able to differentiate between the DNA chain and the protein chain. I either end up with a surface on the DNA which is not fully closed, or if I extend the surface via the 'surface zone' it simply begins to cover the protein as well... I have consulted the documentation and can not find any description of how one would isolate the molecular surface to a particular chain. Is this not possible in Chimera? Cheerio, Jeffrey