This code returns my WordPress menu:
<?php wp_nav_menu( array( 'theme_location' => 'primary', 'menu_class' => 'header-menu') ); ?>
What's the easiest (non-JS) way of adding additional class to all .sub-menu ul dropdowns of this menu?
I was thinking about add_filter() for wp_nav_menu but I'm afraid it will point all wp_nav_menus and I want to add these classes only to this particular one. Also, custom walker sounds a bit like an overkill.
What would you recommend?