I am using Excel 2007 and this is the first time that I have encountered this problem.

When I attempt to copy a cell, not only is the cell I want to copy highlighted, but the cell immediately to the right is also highlighted. There is a small o in the bottom right corner of the second (unwanted) cell.

I can grab the o and move it so that it is in the original cell I want to copy, but this is a painful work-around.

What is going on? How may I fix this? Further compounding the issue is that it does not happen with every cell.