Index: wp-includes/class-wp-walker.php
===================================================================
--- wp-includes/class-wp-walker.php	(revision 23583)
+++ wp-includes/class-wp-walker.php	(working copy)
@@ -130,6 +130,9 @@
 
 		$id = $element->$id_field;
 
+		if( isset( $element->comment_ID ) )
+			do_action( 'after_comment' );
+
 		// descend only when the depth is right and there are childrens for this element
 		if ( ($max_depth == 0 || $max_depth > $depth+1 ) && isset( $children_elements[$id]) ) {