Kendo Grid Custom Filter Dropbox - razor

Question

I am trying to use the custom filtering features of the Kendo Grid. Using Telerik's documentation, I attempted to code the grid per the script below. Notice the "filterable" property on the "Image Type" column. When I pass in a simple boolean true or false, it works. When I use the documentation provided on Telerik's site and pass in a delegate value, it breaks. We're on Kendo version v2013.3.1324. Is this a known issue? Was this area improved after this release?
#(Html.Kendo().Grid<OKN02.Models.ImagingEvent>()
.Name("grid")
.Filterable()
.Sortable()
.Pageable(pageable => pageable
.Refresh(true)
.PageSizes(true)
.ButtonCount(5))
.Scrollable()
.Selectable(selectable => selectable.Mode(GridSelectionMode.Single))
.Columns(columns =>
{
columns.Bound(p => p.ImagingEventId).Hidden();
columns.Bound(p => p.PatientName).Title("Patient Name").Width(90);
columns.Bound(p => p.PatientDOB).Title("DOB").Width(40);
columns.Bound(p => p.Prescriber).Title("Prescriber").Width(80);
columns.Bound(p => p.Site).Title("Site").Width(60);
columns.Bound(p => p.ConfirmationsComplete).Title("Confirmations Complete").Width(90);
columns.Bound(p => p.ImagingDate).Title("Imaging Date").Format("{0:yyyy/MM/dd hh:mm tt}").Width(80);
columns.Bound(p => p.ImageType)
//.Title("Image Type")
.Filterable(filterable => filterable.UI("ImageTypeFilter"))
//.Filterable(true)
.Width(40);
columns.Bound(p => p.OverallStatus).Title("Overall Status").ClientTemplate("#= buildStatusTemplate(OverallStatus) #").Width(40);
})
.Filterable(filterable => filterable
.Extra(true)
.Operators(operators => operators
.ForString(str => str.Clear()
.StartsWith("Starts with")
.IsEqualTo("Is equal to")
.IsNotEqualTo("Is not equal to")
))
)
.Events(events =>
{
events.Change("GridChange");
})
.DataSource(dataSource => dataSource
.Ajax()
.Model(model =>
{
model.Id(p => p.ImagingEventId);
model.Field(p => p.PatientName);
model.Field(p => p.PatientDOB);
model.Field(p => p.Prescriber);
model.Field(p => p.Site);
model.Field(p => p.ImagingDate);
model.Field(p => p.ImagingType);
})
.PageSize(15)
.Read(read => read.Action("MDPortalFiles_Read", "MDPortal").Type(HttpVerbs.Post))
))