Ticket #32791: 32791.patch

src/wp-admin/js/customize-nav-menus.js

@@ -854 +854 @@
                                 content = section.container.find( '.new-menu-section-content' ),
                                 customizer = section.container.closest( '.wp-full-overlay-sidebar-content' );
                         if ( expanded ) {
-                                button.addClass( 'open' );
+                                button.addClass( 'open' ).attr( 'aria-expanded', 'true' );
                                 content.slideDown( 'fast', function() {
                                         customizer.scrollTop( customizer.height() );
                                 });
                         } else {
-                                button.removeClass( 'open' );
+                                button.removeClass( 'open' ).attr( 'aria-expanded', 'false' );
                                 content.slideUp( 'fast' );
                         }
                 }

src/wp-includes/class-wp-customize-section.php

@@ -564 +564 @@
         protected function render() {
                 ?>
                 <li id="accordion-section-<?php echo esc_attr( $this->id ); ?>" class="accordion-section-new-menu">
-                        <button type="button" class="button-secondary add-new-menu-item add-menu-toggle">
+                        <button type="button" class="button-secondary add-new-menu-item add-menu-toggle" aria-expanded="false">
                                 <?php echo esc_html( $this->title ); ?>
-                                <span class="screen-reader-text"><?php _e( 'Press return or enter to open' ); ?></span>
                         </button>
                         <ul class="new-menu-section-content"></ul>
                 </li>