The privileges assigned to a group may allow members of that group to access objects and perform operations that they are otherwise not allowed to do. In other words, privileges override the access rights settings.
In the User Manager dialog box, you will notice that the server configuration comes with some default groups (All Users, Administrators, System Managers, and Security Administrators). The default user named Administrator belongs to both the Administrator and the Security Administrators groups. By default, the Administrator group has all group privileges. Also by default, the other groups have none of these privileges. All members of a group have the same privileges on every project managed by the this server configuration. The privileges apply to all levels equally— projects, views, folders, and items within folders. If users belong to more than one group, they have the maximum amount of privileges, regardless of which group provides them with those privileges.