diff --git a/core/modules/widgets/navigator.js b/core/modules/widgets/navigator.js
index 3d6fb6aec..7809df383 100755
--- a/core/modules/widgets/navigator.js
+++ b/core/modules/widgets/navigator.js
@@ -143,9 +143,11 @@ NavigatorWidget.prototype.addToHistory = function(title,fromPageRect) {
 Handle a tm-navigate event
 */
 NavigatorWidget.prototype.handleNavigateEvent = function(event) {
-	this.addToStory(event.navigateTo,event.navigateFromTitle);
-	if(!event.navigateSuppressNavigation) {
-		this.addToHistory(event.navigateTo,event.navigateFromClientRect);
+	if(event.navigateTo) {
+		this.addToStory(event.navigateTo,event.navigateFromTitle);
+		if(!event.navigateSuppressNavigation) {
+			this.addToHistory(event.navigateTo,event.navigateFromClientRect);
+		}
 	}
 	return false;
 };