The member of tab allows for the configuration of groups to which the user should be made a member of, or removed from.
Determines whether when updating an existing user that user's existing group membership should be retained. When set to false all existing group memberships are removed except the primary group typically the Domain Users group.
Determines the names of the groups to which the user should be made a member, one per line.
Determines the names of the groups from which the user should be removed, one per line. When "Retain Membership" is set to false this field is not available.