diff --git a/lib/ace/mode/xquery.js b/lib/ace/mode/xquery.js
index 93b9c63c..31284f9c 100644
--- a/lib/ace/mode/xquery.js
+++ b/lib/ace/mode/xquery.js
@@ -137,6 +137,8 @@ oop.inherits(Mode, TextMode);
         worker.on("highlight", function(tokens) {
           if(that.$deltas.length > 0) return;
           that.$tokenizer.tokens = tokens.data;
+          session.bgTokenizer.lines = [];
+          session.bgTokenizer.states = [];
           session.bgTokenizer.fireUpdateEvent(0, session.getLength() - 1);
         });