WordPress固定ページカスタマイズ、タグを追加する

コード

themes/functions.php

add_action('init', 'nobita_add_tag_to_page');
add_action( 'pre_get_posts', 'nobita_merge_page_tag_at_tag_archive' );

function nobita_add_tag_to_page() {
 	register_taxonomy_for_object_type('post_tag', 'page');
}

function nobita_merge_page_tag_at_tag_archive( $query ) {
	if ( $query->is_tag== true && $query->is_main_query() ) {
		$query->set('post_type', array( 'post', 'page', 'nav_menu_item'));
	}
}

http://ja.forums.wordpress.org/topic/12991?replies=6(@source)