public function updateTreeTitle(&$title)
    {
        if ($this->owner->AccessAllSubsites) {
            $title = _t(__CLASS__ . '.GlobalGroup', 'global group');
            $title = htmlspecialchars($this->owner->Title, ENT_QUOTES) . ' <i>(' . $title . ')</i>';
        } else {
            $subsites = Convert::raw2xml(implode(', ', $this->owner->Subsites()->column('Title')));
            $title = htmlspecialchars($this->owner->Title) . " <i>($subsites)</i>";
        }
    }