Index: wp-includes/query.php
===================================================================
--- wp-includes/query.php	(revision 21852)
+++ wp-includes/query.php	(working copy)
@@ -3605,7 +3605,8 @@
 	$page = get_query_var('page');
 	if ( !$page )
 		$page = 1;
-	if ( is_single() || is_page() || is_feed() )
+	$more = false;
+	if ( is_single($id) || is_page($id) || is_feed() )
 		$more = 1;
 	$content = $post->post_content;
 	if ( strpos( $content, '<!--nextpage-->' ) ) {