Math + Filter + dynamically added rows

HTML

<link rel="stylesheet" href="http://mottie.github.com/tablesorter/css/theme.blue.css">
<script src="http://mottie.github.com/tablesorter/js/jquery.tablesorter.combined.js"></script>
<script src="http://mottie.github.io/tablesorter/js/widgets/widget-math.js"></script>
<script src="http://mottie.github.io/tablesorter/js/widgets/widget-cssStickyHeaders.js"></script>
<table id="table1" class="tablesorter">
  <thead>
    <tr>
      <th>Foo</th>
      <th>Bar</th>
    </tr>
  </thead>
  <tfoot>
    <tr>
      <th data-math="col-sum">col-sum</th>
      <th data-math="col-sum">col-sum</th>
    </tr>
  </tfoot>

  <tbody>

  </tbody>

</table>

CSS

/* make all calculated values bold */

.tablesorter tbody td[data-math] {
  font-weight: bold;
}


/* darken first & last column */

.tablesorter tbody th,
.tablesorter tbody tr td.totals {
  font-family: 'trebuchet ms', verdana, arial;
  font-size: 13px;
  font-weight: normal;
  background-color: #ddd;
  text-shadow: none;
}


/* even darker tbody info row & tfoot */

.tablesorter tbody.tablesorter-infoOnly th,
.tablesorter tfoot th,
.tablesorter tfoot th.tablesorter-headerAsc,
.tablesorter tfoot th.tablesorter-headerDesc {
  background-color: #aaa;
  font-family: 'trebuchet ms', verdana, arial;
  font-size: 13px;
  font-weight: bold;
  background-color: #aaa;
  text-shadow: none;
}


/* align decimals in Grand Total column */

.align-decimal {
  width: 100px;
  display: inline-block;
  text-align: right;
}

JavaScript

$(function() {

  $('#table1').tablesorter({
    //delayInit: true,
    // debug: true,
    theme: 'blue',
    widgets: ['zebra', 'filter', 'math',
      'cssStickyHeaders'
    ],
    widgetOptions: {
      // math_event: "updateComplete",
      filter_liveSearch: false,
      cssStickyHeaders_filteredToTop: false
    }
  });

  var $scrollEl, scrollPos, scrollTop, undef;

  function updateData() {
    var $tblBody = $("#table1 tbody");
    $tblBody.empty();

    for (var i = 0; i < 20; ++i) {
      $("<tr></tr>")
        .append("<td>" + i + "</td><td>" + (Math.floor(Math.random() * (1000000 - 100000)) + 100000) + "</td>")
        .appendTo($tblBody);
    }

    $("#table1").trigger("update");
  }

  setInterval(updateData, 1000);
});