It's not a public facing page. But the behavior seems very easy to reproduce. It can even be done in FF, chrome, etc.
with this code:
<?php require_once "../cuteeditor_files/include_CuteEditor.php" ?>
<html>
<body>
<form id="form1" method="POST">
<?php
$editor=new CuteEditor();
$editor->Text="<script>window.location='http://www.cutesoft.net';</script>";
$editor->ID="Editor1";
$editor->Draw();
?>
</form>
</body>
</html>
this is the result (loads cutesoft.net in the editor and then you cannot switch to any other view (html/preview):
