From 413a9c99f895f1f2d60a4145d8bac402ac6bb19f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Scott=20Gonz=C3=A1lez?= <scott.gonzalez@gmail.com>
Date: Tue, 24 Mar 2015 14:10:37 -0400
Subject: [PATCH] Core: Handle IE11 bug with document.activeElement in iframes

Fixes #11539
Closes gh-1518

(cherry picked from commit 76c27556f48bea48d3787c241d35e190d46c3245)
---
 ui/core.js | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/ui/core.js b/ui/core.js
index 40703d73d..462d10bb8 100644
--- a/ui/core.js
+++ b/ui/core.js
@@ -57,6 +57,13 @@ $.extend( $.ui, {
 			activeElement = document.body;
 		}
 
+		// Support: IE 11 only
+		// IE11 returns a seemingly empty object in some cases when accessing
+		// document.activeElement from an <iframe>
+		if ( !activeElement.nodeName ) {
+			activeElement = document.body;
+		}
+
 		return activeElement;
 	},