diff --git a/lib/ace/editor.js b/lib/ace/editor.js
index 2e45d887..9e2ea6db 100644
--- a/lib/ace/editor.js
+++ b/lib/ace/editor.js
@@ -264,7 +264,7 @@ var Editor =function(renderer, session) {
         var range = delta.range;
 
         this.bgTokenizer.start(range.start.row);
-        if (range.start.row == range.end.row && delta.action != "insertLines")
+        if (range.start.row == range.end.row && delta.action != "insertLines" && delta.action != "removeLines")
             var lastRow = range.end.row;
         else
             lastRow = Infinity;