diff --git a/lib/ace/background_tokenizer.js b/lib/ace/background_tokenizer.js
index da8008bd..08825d99 100644
--- a/lib/ace/background_tokenizer.js
+++ b/lib/ace/background_tokenizer.js
@@ -68,11 +68,10 @@ var BackgroundTokenizer = function(tokenizer, editor) {
         var endLine = -1;
         var doc = self.doc;
 
+        var startLine = currentLine;
         while (self.lines[currentLine])
             currentLine++;
-
-        var startLine = currentLine;
-
+        
         var len = doc.getLength();
         var processedLines = 0;
         self.running = false;
diff --git a/lib/ace/background_tokenizer_test.js b/lib/ace/background_tokenizer_test.js
index 7a4cc78c..fd738d06 100644
--- a/lib/ace/background_tokenizer_test.js
+++ b/lib/ace/background_tokenizer_test.js
@@ -75,6 +75,49 @@ module.exports = {
         
         forceTokenize(doc)
         testStates(doc, ["comment_regex_allowed", "start", "no_regex"])
+    },
+    "test background tokenizer sends update event" : function() {
+        var doc = new EditSession([
+            "/*",
+            "var",
+            "juhu",
+            "*/"
+        ]);
+        doc.setMode("./mode/javascript");
+        
+        var updateEvent = null;
+        doc.bgTokenizer.on("update", function(e) {
+            updateEvent = e.data;
+        });
+        function checkEvent(first, last) {
+            assert.ok(!updateEvent, "unneccessary update event");
+            doc.bgTokenizer.running = 1;
+            doc.bgTokenizer.$worker();
+            assert.ok(updateEvent);
+            assert.equal([first, last] + "", 
+                [updateEvent.first, updateEvent.last] + "")
+            updateEvent = null;
+        }
+        
+        forceTokenize(doc);
+        var comment = "comment_regex_allowed";
+        testStates(doc, [comment, comment, comment, "start"]);
+        
+        doc.remove(new Range(0,0,0,2));
+        testStates(doc, [comment, comment, comment, "start"]);
+        
+        checkEvent(0, 3);
+        testStates(doc, ["start", "no_regex", "no_regex", "regex"]);
+        
+        // insert /* and and press down several times quickly
+        doc.insert({row:0, column:0}, "/*");
+        doc.getTokens(0);
+        doc.getTokens(1);
+        doc.getTokens(2);
+        checkEvent(0, 3);
+        
+        forceTokenize(doc);
+        testStates(doc, [comment, comment, comment, "start"]);
     }
 };