Index: wp-includes/post-template.php
===================================================================
--- wp-includes/post-template.php	(revision 21850)
+++ wp-includes/post-template.php	(working copy)
@@ -188,6 +188,13 @@
 	$output = '';
 	$hasTeaser = false;
 
+	// Only disable <!--more--> tag if we're displaying the is_single post itself
+	$show_full_content = $more;
+	if ( is_single() OR is_page() ) {
+		if ($post->ID != get_queried_object_id())
+			$show_full_content = false;
+	}
+	
 	// If post password required and it doesn't match the cookie.
 	if ( post_password_required() )
 		return get_the_password_form();
@@ -208,11 +215,11 @@
 	if ( (false !== strpos($post->post_content, '<!--noteaser-->') && ((!$multipage) || ($page==1))) )
 		$stripteaser = true;
 	$teaser = $content[0];
-	if ( $more && $stripteaser && $hasTeaser )
+	if ( $show_full_content && $stripteaser && $hasTeaser )
 		$teaser = '';
 	$output .= $teaser;
 	if ( count($content) > 1 ) {
-		if ( $more ) {
+		if ( $show_full_content ) {
 			$output .= '<span id="more-' . $post->ID . '"></span>' . $content[1];
 		} else {
 			if ( ! empty($more_link_text) )