This dialog box allows you to specify whether you want to view the VSS database version of the file you double-clicked, or would prefer to edit this checked-out file in your working folder.
You will see this dialog box only if you have specified that it should be presented when a file is double-clicked in the VSS Explorer. You can change this specification from the Tools Options General tab. Or, if you hold the SHIFT key down while double-clicking a file in the Explorer, this dialog will always be presented regardless of the setting on the Tools Options General tab.
In this dialog, select your choice (or click Cancel to cancel the operation) and click OK.