Ticket #28969: 28969.diff

src/wp-includes/js/media-grid.js

@@ -463 +463 @@
 
                                 this.modal.on( 'open', function () {
                                         $( 'body' ).on( 'keydown.media-modal', _.bind( self.keyEvent, self ) );
+                                        $( '.media-modal-close' ).blur();
                                 } );
 
                                 // Completely destroy the modal DOM element when closing it.