try cm.refresh in textbox.html to fix codemirror bug with chrome

templates/textbox.html

@@ -29,6 +29,7 @@ $(function(){
                                      , lineNumbers: true
 % endif
 				   });
+  cm.refresh();
   // codemirror_set["${id}"] = cm;	// track it for refreshes
 });
 </script>