Ticket #30722: 30722.2.diff

src/wp-content/themes/twentyfifteen/js/functions.js

@@ -13 +13 @@
         // Add dropdown toggle that display child menu items.
         $( '.main-navigation .menu-item-has-children > a' ).after( '<button class="dropdown-toggle" aria-expanded="false">' + screenReaderText.expand + '</button>' );
 
+        // Toggle buttons and submenu items with active children menu items
+        $( '.main-navigation .current-menu-ancestor > button' ).addClass( 'toggle-on' );
+        $( '.main-navigation .current-menu-ancestor > .sub-menu' ).addClass( 'toggled-on' );
+
         $( '.dropdown-toggle' ).click( function( e ) {
                 var _this = $( this );
                 e.preventDefault();