I'm using ArcGIS Earth to view KML/KMZ files and when opening the file from Windows Explorer (ie, double clicking the file from the desktop) if I've got the file open in ArcGIS Earth already it adds the file again as a new layer. The ideal behaviour would be present the user with an option to re-open/refresh the file, or to add a new layer. Also give the user an option to set a default action (ie "always refresh").
