// ------------------------------------------------------ callback methods triggered by the view
public void launchAddRoleAssignmentWizard(final Principal.Type type) {
String title = type == USER ? Console.CONSTANTS.administration_add_user_assignment() : Console
.CONSTANTS.administration_add_group_assignment();
openWindow(title, 480, 630, new AddRoleAssignmentWizard(this, type, principals, roles).asWidget());
}