diff --git a/IPython/html/static/base/js/utils.js b/IPython/html/static/base/js/utils.js
index a3131a1ed..61eb84ab7 100644
--- a/IPython/html/static/base/js/utils.js
+++ b/IPython/html/static/base/js/utils.js
@@ -548,6 +548,7 @@ define([
             return;
         }
         require([
+                // might want to use CodeMirror.modeURL here
                 ['codemirror/mode', mode, mode].join('/'),
             ], callback, errback
         );