The following code causes an endless loop such that the dialog in question appears to be repeatedly appended to the end of the page. The vertical scroll gets longer and longer, but if you scroll down fast enough, you can see the dialog flickering. The offending code is in bold. I do not get this in 1.4.2 but I do get it with 1.4.4 and 1.5.1 as well.

    $(document).ready(
        function () {
            $("#modal-dialog").dialog({
                autoOpen: false,
                modal: true,
                width: 350,
                height: 235,
                closeOnEscape: false,
                draggable: false,
                resizable: false,
                open: function (event, ui) {
  '''                  $('#refresh').bind("keypress", function (e) {
                        if (e.keyCode == 13 && $(e.target).is(':input')) {
                            $('#btnRefreshLogon').click();
                        }
                    }'''
                    );
                },
                close: function (event, ui) { $('#refresh').unbind('keypress'); }
            });
        }
    );