Index: touch-keyboard-navigation.js
===================================================================
--- touch-keyboard-navigation.js	(revision 51468)
+++ touch-keyboard-navigation.js	(working copy)
@@ -274,7 +274,7 @@
 
 		document.addEventListener('focus', function(event) {
 
-			if ( event.target.matches('.main-navigation > div > ul > li a') ) {
+			if ( event.target != window.document && event.target.matches('.main-navigation > div > ul > li a') ) {
 
 				// Remove Focused elements in sibling div.
 				var currentDiv        = getCurrentParent( event.target, 'div', '.main-navigation' );