This is a bug in both Q1 and Q2 2011 - the only solution I've been able to come up with is to rollback to Version 2010.3.1318...
When using DatePickerFor:
@Html.Telerik().DatePickerFor(sc => sc.StartDate).ShowButton(true)
When I delete the date in the TextBox of the DatePicker, post my form, fail validation, then re-display the view, I get a NullReferenceException where the DatePicker is being rendered. The view is a strongly-typed view and the actual value of StartDate (in the controller and in the re-displayed view) is DateTime.MinValue (which I expected).
With NO CHANGES IN CODE, this problem is resolved by going back to Version 2010.3.1318 so it seems that the issue was introduced some time after that release.
I'd like to use the latest version of the controls - when do you think this might be fixed?
Thanks...