MVC Grid Groupable greyed out when dragging column

[Scott]

Here is my Razor grid markup...

 

@(Html.Kendo().Grid<Karpos.WebUI.Models.HolidayDinnerModel>(Model) //Bind the grid to ViewBag.Products
                    .Name("grid")
                    .Columns(columns =>
                    {
                        columns.Bound(model => model.PLU).Groupable(true);
                        columns.Bound(model => model.Name);
                    })
                    .Pageable() //Enable the paging.
                    .Sortable() //Enable the sorting.
                    .Groupable()

)

 

The grid loads with data correctly but when I try to drag the PLU column to the Head to group on PLU, it is greyed out. All columns are the same way.

 

Any help?

[Scott]

I found out that I had some other javascript files that were interfering with the grid.