Removed possibility to subordinate a file to itself or one of it's subordinates.

edit/page.php

@@ -133,6 +133,7 @@ echo '
                     <select name="higher" id="higher">
                         <option value="0"></option>';
 foreach ($pages as $page) {
+    if (isset($id) && $page['id'] == $id or $page['higher'] == $id) continue;
     echo '<option value="' . $page['id'] . '"';
     if (isset($higher) and $page['id'] == $higher) echo " selected";
     echo '>' . $page['title'] . '</option>';