I have an excel file that includes email addresses.
I choose which address I need by holding the Control key and selecting
specific cells - then Control C to copy them and then paste them with Control
V into the "To" for recipients to send them mail.

Sometimes this works perfectly and other times it pastes the entire row of
email addresses even though it only shows the ones I've chosen and copied as
highlighted.

Any idea why sometimes it pastes more than I've copied?