I'd be you'll want to keep both workbooks in the same instance of excel.
Otherwise, you may not get the choices you want when you do the copy|paste.

If you're using multiple monitors, you may want to review Chip Pearson's notes:
http://cpearson.com/excel/MultipleMonitors.aspx

Penny wrote:

I have two screens which I work from and I want to have one excel document
(full workbook) on one screen and another fullw orkbook on the other screen
as it makes it easier to cut and paste.

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Dave Peterson