Making toolbox part independent doesn't seem to severe it's connections to toolbox, and when modified, it reverts upon reopening and messes up the assembly.

Making toolbox part independent doesn't seem to severe it's connections to toolbox, and when modified, it reverts upon reopening and messes up the assembly.  That's pretty much the problem I have.  I'm using a piece of box tubing from the toolbox, but I need to add features to it.  Nothing I do seems to break it's toolbox links, from saving as in a new location, to making it independent, to renaming it and breaking all ext. refs. 

ANY IDEAS?

Thanks,

A

SolidworksAssemblies