CA Sheet Problem

We have discovered an ingenious new problem plaguing the CA scheduling
spreadsheet. I do not know how this happened, but here is the symptom. You
open a spreadsheet and you see a little version number behind the name like 1
or 2. For example:

ca1212.xls:1
ca1212.xls:2

Sometimes you may see a file's name several times under Window as if you
somehow have several copies of the same spreadsheet open. This apparently
results from selecting Window < New Window. Never, ever select New Window!
I repeat: NEVER, EVER SELECT NEW WINDOW! Once a worksheet has this version
number it is "contaminated" and all sorts of other problems appear. I'm sure
you have noticed new errors popping up when you open or close one of these
files.

I am going to create a new worksheet for the 13th from an older file that
does not have one of these version numbers. And we will hope this doesn't
happen again. Please be careful with this. It sounds trivial but can in
fact really screw things up.