function pre_get_posts( $query ){
if(isset($query->getpostlist) && $query->getpostlist) {
add_filter( 'posts_fields', 'postsetupFields', 20);
} else {
remove_filter( 'posts_fields', 'postsetupFields', 20);
}
return $query;
}
function postsetupFields( $fields ){
global $wpdb;
$fields = "{$wpdb->posts}.ID";
return $fields;
}
add_action( 'pre_get_posts', 'postsetupFields');