diff --git a/lib/util/runmode.js b/lib/util/runmode.js
index de4a760202..a5872abdc8 100644
--- a/lib/util/runmode.js
+++ b/lib/util/runmode.js
@@ -1,5 +1,5 @@
 CodeMirror.runMode = function(string, modespec, callback) {
-  var mode = CodeMirror.getMode({indentUnit: 2}, modespec);
+  var mode = CodeMirror.getMode(CodeMirror.defaults, modespec);
   var isNode = callback.nodeType == 1;
   if (isNode) {
     var node = callback, accum = [];