Index: wp-includes/class-wp-walker.php
===================================================================
--- wp-includes/class-wp-walker.php	(revision 21494)
+++ wp-includes/class-wp-walker.php	(working copy)
@@ -125,6 +125,8 @@
 		//display this element
 		if ( is_array( $args[0] ) )
 			$args[0]['has_children'] = ! empty( $children_elements[$element->$id_field] );
+		else if ( is_object( $args[0] ) )
+			$args[0]->has_children = ! empty( $children_elements[$element->$id_field] );
 		$cb_args = array_merge( array(&$output, $element, $depth), $args);
 		call_user_func_array(array(&$this, 'start_el'), $cb_args);