diff --git a/lib/client/keyBinding.js b/lib/client/keyBinding.js
index 1574acc7..06f10f30 100644
--- a/lib/client/keyBinding.js
+++ b/lib/client/keyBinding.js
@@ -29,8 +29,9 @@ CloudCommander.MOUSE_BUTTON = {
 
 CloudCommander.mouseBinding = (function(){
     document.onmousedown = function(){        
-        if(event.button === CloudCommander.MOUSE_BUTTON.RIGHT)
-            CloudCommander.Menu();
+        if(typeof CloudCommander.Menu === 'function' &&
+            event.button === CloudCommander.MOUSE_BUTTON.RIGHT)
+                CloudCommander.Menu();
     };
 })