Klasse zu Submenü hinzufügen

add_filter( 'nav_menu_submenu_css_class', 'some_function', 10, 3 ); 
function some_function( $classes, $args, $depth ){ 
	foreach ( $classes as $key => $class ) { 
		if ( $class == 'sub-menu' ) { 
			$classes[ $key ] = 'my-sub-menu'; 
			} 
		} 
	return $classes; 
} 

Quelle: https://stackoverflow.com/questions/5034826/wp-nav-menu-change-sub-menu-class-name