Excel 2002 SP3
XP Pro SP2

I received two spreadhseets from my boss that I'm supposed to geocode.
Anyway, to the left of the row numbers is a collapsable bracket-type control
that you see in things like Windows Explorer, etc. There are "+" boxes and
"-" boxes, and best I can tell they hide or unhide rows. I've never seen
anything like this; can somebody identify this? Is it a Lotus control or
something?