public function display($tpl = null)
 {
     parent::display($tpl);
     $layout = JRequest::getCmd('layout', '');
     $outline = WorkflowHelper::getOutline();
     $slides = array_keys($outline);
     $index = array_search($layout, $slides);
     $back = false;
     $next = false;
     if ($index > 0) {
         $back = $slides[$index - 1];
     }
     if ($index < count($outline) - 1) {
         $next = $slides[$index + 1];
     }
     include 'nav.php';
 }
 public function display($tpl = null)
 {
     $outline = WorkflowHelper::getOutline();
     $this->assignRef('outline', $outline);
     parent::display($tpl);
 }