Renaming Materials - why is number added?

Often when designing a part, we know we want "steel", buthaven't decided about a specific form of steel, or just don't carewhich kind. So, we just copied one of the steels, and just renamedit to say simply, "steel".

But, a number always gets appended, so it actually gets named"Steel (21)". I can't delete that "(21)" part.

Can anyone explain what is going on?

Joe DunfeeSolidworksGeneral