Please try to override the treegrid view to solve this issue.
<script>
(function($){
render = $.fn.treegrid.defaults.view.render;
$.extend($.fn.treegrid.defaults.view, {
render: function(target, container, frozen){
$(container).children('table.datagrid-btable-stub').remove();
render.call(this, target, container, frozen);
var state = $.data(target, 'treegrid');
var dc = state.dc;
if (dc.body2.is(':empty')){
var fields = $(target).treegrid('getColumnFields', frozen);
var table = ['<table class="datagrid-btable-stub" cellspacing="0" cellpadding="0" border="0"><tbody>'];
table = table.concat(this.renderRow.call(this, target, fields, frozen, 0, {}));
table.push('</tbody></table>');
$(container).html(table.join(''));
$(container).find('div').height(0);
}
}
})
})(jQuery);
</script>