.Columns having no effect when creating Kendo Grid through Custom HtmlHelper

[Richard]

I have the following code to create a Kendo Grid inside my custom HtmlHelper. The Ajax will return a 3 column data set to the DataSource (ID, Number, Name). No matter what I do, the Grid will return all the columns, and even if I try to change the title of the Number column to "Test Column" it has no effect. What am I missing? 

public static IHtmlContent FilterGrid<T>(this IHtmlHelper<T> html, string Name, string Controller) where T : class
        {
            HtmlContentBuilder htmlBuilder = new HtmlContentBuilder();

            htmlBuilder.AppendHtml(html.Kendo().DataSource<T>()
                .Name("ds_" + Name)
                .Ajax(dataSource => dataSource
                        .PageSize(20)
                        .Read(read => read.Action(Name + "_Read", Controller))
                    )
            );           

            htmlBuilder.AppendHtml(html.Kendo().Grid<T>()
                .Name("g_" + Name)
                .Pageable()
                .Sortable()
                .NoRecords()
                .DataSource("ds_" + Name)
                .Filterable(ftb => ftb.Mode(GridFilterMode.Row))
                .Columns(c => {
                    c.Bound("Number").Title("Test title");
                    })
            ); 
            return htmlBuilder;
        }

[Stephen]

Turns out it was caused by the persisting of the state of the grid in local storage.