Ticket #23026: parent_dropdown_fix.patch

wp-admin/includes/template.php

@@ -677 +677 @@
         $post = get_post();
         $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) );
 
-        if ( $items ) {
+        if ( $post && $items ) {
                 foreach ( $items as $item ) {
                         // A page cannot be its own parent.
                         if ( $post->ID && $item->ID == $post->ID )