Index: wp-admin/includes/template.php
===================================================================
--- wp-admin/includes/template.php	(revision 17581)
+++ wp-admin/includes/template.php	(working copy)
@@ -675,7 +675,7 @@
  */
 function parent_dropdown( $default = 0, $parent = 0, $level = 0 ) {
 	global $wpdb, $post_ID;
-	$items = $wpdb->get_results( $wpdb->prepare("SELECT ID, post_parent, post_title FROM $wpdb->posts WHERE post_parent = %d AND post_type = 'page' ORDER BY menu_order", $parent) );
+	$items = $wpdb->get_results( apply_filters( 'parent_dropdown_query', $wpdb->prepare("SELECT ID, post_parent, post_title FROM $wpdb->posts WHERE post_parent = %d AND post_type = 'page' ORDER BY menu_order", $parent ), $parent, 'page' ) );
 
 	if ( $items ) {
 		foreach ( $items as $item ) {