Ok... I've noticed an odd occurence while working on a certain assembly in recent days.  This assembly, which contains about 100 parts/subassemblies and has 3 configurations, shows as being altered immediately upon opening regardless of what I don't do to it.  It appears this is only an issue with the top assembly and none of the parts themselves.  This is obviously not a serious matter, but just one that has me a bit confused.  Anyone know why this may be happening?

Thanks