Attempt to fix Hint compatibility problem (WIP)

Change-Id: I3016afc2f74b90c223dd4f8f2386b71aab1eedcd
diff --git a/dev/js/src/hint/prefix.js b/dev/js/src/hint/prefix.js
index dc14d5c..197e36e 100644
--- a/dev/js/src/hint/prefix.js
+++ b/dev/js/src/hint/prefix.js
@@ -1,3 +1,5 @@
+"use strict";
+
 define(['menu/prefix'], function (prefixClass) {
   return {