Fix for broken menu_order

Add to Common Functions

/**
 * WP 3.5 doesn't update menu_order for ordering attachments, so this function updates the menu_order so that you can orderby menu_order
 * @param int $id
 */
function pmc_gallery_menu_order_fix($id) {
        $regex_pattern = get_shortcode_regex();
        preg_match ('/'.$regex_pattern.'/s', stripslashes($_POST['content']), $regex_matches);
        if ( ! $regex_matches ) {
                return false;
        }
        if ($regex_matches[2] == 'gallery') {
            $attribure_str = str_replace(" ", "&", trim ($regex_matches[3]));
            $attribure_str = str_replace('"', '', $attribure_str);
            $attributes = wp_parse_args($attribure_str);
        }
        $ids = explode(',', $attributes[ids]);
        $images = get_posts( array(
		'post_parent' => $post->ID,
		'numberposts' => '-1',
		'post_status' => 'inherit',
		'post_type' => 'attachment',
		'post_mime_type' => 'image',
		'orderby' => 'menu_order ID',
		'order' => 'ASC'
	) );
	if ( $images ) {
		foreach ( $images as $attachment_id => $attachment ) {
			if (in_array($attachment->ID, $ids)) {
				$update_post = array();
				$update_post['ID'] = $attachment->ID;
				$update_post['menu_order'] = array_search($attachment->ID, $ids);
				wp_update_post( $update_post );
			};
		}
	}
}
add_action('pre_post_update', 'pmc_gallery_menu_order_fix');