iv class="panel-body">
              Column filter, header row, (using Chromium does not render row over 210k px)
            </div>
          </div>
        </div>
        <div class="row">

          <div class="col-md-8">
          Turn on header row by given 2 options
          <pre><code class='dart'>
  Map opt = {
     'showHeaderRow': true,
     'headerRowHeight': 25
  };
</code></pre>
          Add handler to render  header cell
          <pre><code class='dart'>
  sg.onHeaderRowCellRendered.subscri