diff --git a/core/metamodel.class.php b/core/metamodel.class.php
index ef245bf92..0aeee31bf 100644
--- a/core/metamodel.class.php
+++ b/core/metamodel.class.php
@@ -1261,7 +1261,7 @@ abstract class MetaModel
 
 		// Build the list of available extensions
 		//
-		$aInterfaces = array('iApplicationUIExtension', 'iApplicationObjectExtension', 'iQueryModifier', 'iOnClassInitialization');
+		$aInterfaces = array('iApplicationUIExtension', 'iApplicationObjectExtension', 'iQueryModifier', 'iOnClassInitialization', 'iPopupMenuExtension');
 		foreach($aInterfaces as $sInterface)
 		{
 			self::$m_aExtensionClasses[$sInterface] = array();