I'm sure this is all logical and stuff, but I can't get my head around it.
Frequently, when I edit a part of a sub-assembly of some larger assembly, I get this message:
"This part has features defined in the context of another assembly . You can edit the part, but you cannot create external references to the components of the current assembly."
What bugs me is that sometimes I edit parts of sub-assemblies which darn well have references to a greater assembly, and SW happily lets me add references that are local to the sub assembly. Yet sometimes it displays the above message and doesn't let me do it. Of course there's no problem editing the part in the context of the top assembly, but since the references I intend to add are strictly within the context of the sub-assembly the logic of it all escapes me.