Reply To: Filter collapse option?

Thank you, it will be definitely added in a later release 🙂

I think that is also possible, try chaning the first recommended code to:

add_filter('wp_footer', 'asp_my_custom_script', 10);
function asp_my_custom_script() {
  ?>
  <script>
  jQuery(function($) {
    $('.asp_ss fieldset>legend').on('click', function(){
		$(this).closest('fieldset').toggleClass('asp_filter_opened');
	});
    $('.asp_filter_cf_locatie legend').trigger('click');
  });
  </script>
  <?php
}