Spreadspeed operations that alter the content or formatting of the workbook will have a "Save workbook ..." option on the dialog. Add-ins do not have access to the built-in undo / redo operations of Excel, so the save option is included to ensure that you can revert back to the previous state of the workbook using Close and Re-Open Last Save. The Close and Re-Open Last Save tool will close the workbook without saving and then open it again.