I just noticed something very strange when opening an Excel document that is in Excel 97-2003 format. This is the file system before I open the file: Then I open the file using Excel 2007. I do nothing to the file. It is opened in compatibility mode. The file system now looks like this: The last modified date changed! As strange as that is, it gets even stranger. Now if I close Excel, I don't get any warnings and the file system now looks like this: I kid you not! That is a new screenshot, not a...