I have an Excel spreadsheet that has Coulmns A-P. I have been using the same
spreadsheet for seven years. Today when I opened it on the right hand side
of the screen is a grayish colored bar between the coulmns and to the right
of it is the same exact spreadsheet with the identical number of coulmns and
data is all the same. How do I get rid of this duplicate spreadsheet and why
did it show up?

Thanks