public function addDisplayGroup(array $elements, $name)
    {
        $group = $this->newDisplayGroup();
        foreach ($elements as $element) {
            if (isset($this->_elements[$element])) {
                $add = $this->getElement($element);
                if (null !== $add) {
                    $group->addElement($add);
                }
            }
        }
        if (empty($group)) {
            trigger_error('No valid elements specified for display group');
        }

        $name = (string)$name;
        $group->setLegend($name);

        $this->_displayGroups[$name] = $group;

        return $this;
    }