While working with assemblies in NX, your parts' reference sets can pick up a lot of junk. Ok, maybe the junk is perfectly good and useable geometry, but you often don't want to keep it where NX put it. These extras show up from operations like wave linking, working in context of an assembly, importing/exporting geometry, etc etc. The reference set dialog will gladly tell you how many objects are in a given reference set, but it stubbornly refuses to show you where they are.
