From f1c40eeccc4b6da1f0cd00be995285eeec7923f0 Mon Sep 17 00:00:00 2001
From: Toby Zerner <toby.zerner@gmail.com>
Date: Fri, 25 Sep 2015 23:21:10 +0930
Subject: [PATCH] Prevent empty beforeunload dialog on Internet Explorer

---
 js/forum/src/components/Composer.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/js/forum/src/components/Composer.js b/js/forum/src/components/Composer.js
index 05d50234e..0bcdb72d9 100644
--- a/js/forum/src/components/Composer.js
+++ b/js/forum/src/components/Composer.js
@@ -124,7 +124,7 @@ class Composer extends Component {
     // component a chance to scream at the user to make sure they don't
     // unintentionally lose any contnet.
     window.onbeforeunload = () => {
-      return (this.component && this.component.preventExit()) || null;
+      return (this.component && this.component.preventExit()) || undefined;
     };
 
     const handlers = {};