function proov_add_custom_types( $query ) {
// add condition to make sure it's the the main query
if( is_category() || is_tag() && empty( $query->query_vars['suppress_filters'] )
&& $query->is_main_query() ) {
$query->set( 'post_type', array(
'post', 'nav_menu_item', 'oeuvre'
));
return $query;
}
}
add_filter( 'pre_get_posts', 'proov_add_custom_types' );