wpsight_search_locations_top.php

<?php
/**
 * Only top level locations
 * in search form
 */
 
add_filter( 'wpsight_search_form_details', 'custom_search_form_details', 100 );
 
function custom_search_form_details( $details ) {
 
    $details['location']['data'] = get_terms( 'location', array( 'orderby' => 'name', 'hide_empty' => true, 'parent' => 0, 'hierarchical' => false ) );
 
    return $details;
 
}