Send the time the Workbook was initially opened

[AndyLockhartHSBC]

Current the Still Open message sends the path of the Workbook and the total time that the workbook was open. Some organisations might find it beneficial to know when the workbook was first opened to help spot any patterns, i.e. Person X opens Workbook Y around 8am every day.
This information might indicate that it's a workbook that would be useful to focus on.