SW 2010 Won't Let me Remove Appearance

I'm trying to remove an appearance but it won't let me.  I have a subassembly that I added an appearance to within the assembly and I can't remove it now.  The first image shows where they are technically locating the appearance for the piping subassembly. In the second image you can see that remove appearance is greyed out.  Anybody have any suggestions?

SolidworksGeneral