To change the Gmail login credentials, you can use the Login As... menuitem under the File menu. Place a checkmark in the Auto Login entry to automatically login when the folder is activated. Your username and password are securely stored in the System Registry with encryption.
If you are behind a proxy, the tool will use the Proxy Settings of your Microsoft Internet Explorer browser. If proxy authentication (username and password) is needed, you can add this information to the Login dialog under the More button panel.
Only one user can be logged in at any time. This allows GMail Drive to optimize the folder cache it holds during file activity.