Index: wp-content/themes/twentyfourteen/js/featured-content-admin.js
===================================================================
--- wp-content/themes/twentyfourteen/js/featured-content-admin.js	(revision 27851)
+++ wp-content/themes/twentyfourteen/js/featured-content-admin.js	(working copy)
@@ -5,5 +5,5 @@
 /* global ajaxurl:true */
 
 jQuery( document ).ready( function( $ ) {
-	$( '#customize-control-featured-content-tag-name input' ).suggest( ajaxurl + '?action=ajax-tag-search&tax=post_tag', { delay: 500, minchars: 2 } );
+	$( '#customize-control-featured-content-tag-name input' ).suggest( ajaxurl + '?action=ajax-tag-search&tax=post_tag', { delay: 500, minchars: 2, onSelect: function() { $( this ).change() } } );
 });