Do you put gas in your car? Do you change the oil in your car? Same concept on your web site. You MUST maintain your web site or it will break down.
Gravity theme creates a large folder in the root directory which will eventaully cause the File Manager to not load.
We have a client who uses AD Authentication on their DNN web site. They wanted the Windows Login tab to be the primary tab and when a user pressed enter for them to log into the web site.