diff --git a/lib/ace/mode/text.js b/lib/ace/mode/text.js
index 34a2a511..f04f1722 100644
--- a/lib/ace/mode/text.js
+++ b/lib/ace/mode/text.js
@@ -62,7 +62,7 @@ var Mode = function() {
 
     this.getTokenizer = function() {
         if (!this.$tokenizer) {
-            this.$highlightRules = new this.HighlightRules();
+            this.$highlightRules = this.$highlightRules || new this.HighlightRules();
             this.$tokenizer = new Tokenizer(this.$highlightRules.getRules());
         }
         return this.$tokenizer;
diff --git a/lib/ace/tokenizer.js b/lib/ace/tokenizer.js
index 72989766..64bf59e8 100644
--- a/lib/ace/tokenizer.js
+++ b/lib/ace/tokenizer.js
@@ -116,6 +116,11 @@ var Tokenizer = function(rules) {
                 rule.onMatch = null;
         }
         
+        if (!ruleRegExps.length) {
+            mapping[0] = 0;
+            ruleRegExps.push("$");
+        }
+        
         splitterRurles.forEach(function(rule) {
             rule.splitRegex = this.createSplitterRegexp(rule.regex, flag);
         }, this);