mvc grid grouping is not working

[turkush .]

Hi,

with ref of following page.

http://demos.telerik.com/aspnet-mvc/grid/ajaxbinding

<%= Html.Telerik().Grid<Order>()
        .Name("Grid")
        .Columns(columns =>
        {
            columns.Bound(o => o.OrderID).Width(100);
            columns.Bound(o => o.Customer.ContactName).Width(200);
            columns.Bound(o => o.ShipAddress);
            columns.Bound(o => o.OrderDate).Format("{0:MM/dd/yyyy}").Width(120);
        })
        .DataBinding(dataBinding => dataBinding.Ajax().Select("_AjaxBinding", "Grid"))
        .Pageable()
        .Sortable()
        .Scrollable()
        .Groupable()
        .Filterable()
%>

I tried above code but im unable to have grid grouping the colums are not geting draged and droped on the area reserved for grouping.