diff -r c7c34916027a -r 177826044cd9 wp/wp-includes/js/wpdialog.js
--- a/wp/wp-includes/js/wpdialog.js	Mon Oct 14 18:06:33 2019 +0200
+++ b/wp/wp-includes/js/wpdialog.js	Mon Oct 14 18:28:13 2019 +0200
@@ -1,3 +1,10 @@
+/**
+ * @output wp-includes/js/wpdialog.js
+ */
+
+/*
+ * Wrap the jQuery UI Dialog open function remove focus from tinyMCE.
+ */
 ( function($) {
 	$.widget('wp.wpdialog', $.ui.dialog, {
 		open: function() {
@@ -8,6 +15,7 @@
 
 			// Open the dialog.
 			this._super();
+
 			// WebKit leaves focus in the TinyMCE editor unless we shift focus.
 			this.element.focus();
 			this._trigger('refresh');