diff --git a/classes/template/PKPTemplateManager.php b/classes/template/PKPTemplateManager.php
index eb0974f4d2a..34b27c134bd 100644
--- a/classes/template/PKPTemplateManager.php
+++ b/classes/template/PKPTemplateManager.php
@@ -306,6 +306,7 @@ public function initialize($request)
         $this->registerPlugin('modifier', 'strstr', strstr(...));
         $this->registerPlugin('modifier', 'strval', strval(...));
         $this->registerPlugin('modifier', 'array_key_first', array_key_first(...));
+        $this->registerPlugin('modifier', 'array_values', array_values(...));
         $this->registerPlugin('modifier', 'fatalError', fatalError(...));
         $this->registerPlugin('modifier', 'translate', $this->smartyTranslateModifier(...));
         $this->registerPlugin('modifier', 'strip_unsafe_html', \PKP\core\PKPString::stripUnsafeHtml(...));
@@ -1328,7 +1329,7 @@ public static function &getManager($request = null)
         }
         assert($request instanceof PKPRequest);
 
-        $instance = & Registry::get('templateManager', true, null); // Reference required
+        $instance = &Registry::get('templateManager', true, null); // Reference required
 
         if ($instance === null) {
             $instance = new TemplateManager();
@@ -1368,9 +1369,9 @@ public function getFBV()
      */
     public function displaySidebar($hookName, $args)
     {
-        $params = & $args[0];
-        $smarty = & $args[1];
-        $output = & $args[2];
+        $params = &$args[0];
+        $smarty = &$args[1];
+        $output = &$args[2];
 
         if ($this->_request->getContext()) {
             $blocks = $this->_request->getContext()->getData('sidebar');