Apparently explorer.exe command line switches no longer work properly in Windows 7 (I would guess 8 too). So, the Tool suggested in one thread that opens an Explorer window on a selected file doesn't work. Instead, Windows Explorer just opens a default Window to My Documents.
Any chance we can see an "Open Folder" command in MP3TAG? Or are there any suggestions on how to work around this? (I'm working with MP3+CDG files all the time so I need to use Explorer frequently to check them.)