Index: lams_monitoring/web/includes/javascript/monitorLesson.js
===================================================================
diff -u -r00a56a2712593b8d628581120151259020c1c67e -r8697dc33eefb5888cfba47cf957c7b7eeed78d96
--- lams_monitoring/web/includes/javascript/monitorLesson.js	(.../monitorLesson.js)	(revision 00a56a2712593b8d628581120151259020c1c67e)
+++ lams_monitoring/web/includes/javascript/monitorLesson.js	(.../monitorLesson.js)	(revision 8697dc33eefb5888cfba47cf957c7b7eeed78d96)
@@ -1746,6 +1746,10 @@
  * Escapes HTML tags to prevent XSS injection.
  */
 function escapeHtml(unsafe) {
+	if (unsafe == undefined) {
+		return "";
+	}
+	
     return unsafe
         .replace(/&/g, "&")
         .replace(/</g, "&lt;")