diff --git a/lib/ace/editor.js b/lib/ace/editor.js
index ac7c31ac..834e603a 100644
--- a/lib/ace/editor.js
+++ b/lib/ace/editor.js
@@ -509,8 +509,9 @@ var Editor = function(renderer, session) {
             this.$updateHighlightActiveLine();
         }
 
+        var self = this;
         if (this.$highlightSelectedWord && !this.$wordHighlightTimer)
-            this.$wordHighlightTimer = setTimeout(function(self) {
+            this.$wordHighlightTimer = setTimeout(function() {
                 self.session.$mode.highlightSelection(self);
                 self.$wordHighlightTimer = null;
             }, 30, this);