Index: branches/RC/core/admin_templates/js/calendar/calendar.js
===================================================================
diff -u -N -r11528 -r11925
--- branches/RC/core/admin_templates/js/calendar/calendar.js	(.../calendar.js)	(revision 11528)
+++ branches/RC/core/admin_templates/js/calendar/calendar.js	(.../calendar.js)	(revision 11925)
@@ -124,12 +124,19 @@
 			related = evt.toElement;
 		}
 	}
-	while (related) {
-		if (related == el) {
-			return true;
+
+	try {
+		while (related) {
+			if (related == el) {
+				return true;
+			}
+			related = related.parentNode;
 		}
-		related = related.parentNode;
 	}
+	catch (e) {
+
+	}
+
 	return false;
 };