CreateNew() appointment returns nothing

[Kenneth]

CreateNew returns nothing, appointmentcreating event not fired.

All assemblies referenced per documentation.  

I also tried setting an appointment source in code as follows with no effect:

ScheduleView.AppointmentsSource = New List(Of IAppointment)

in xaml:

<telerik:RadScheduleView Name="ScheduleView" Margin="20">
            <telerik:RadScheduleView.ViewDefinitions>
                <telerik:MonthViewDefinition  />
                <telerik:DayViewDefinition />
                <telerik:WeekViewDefinition />
            </telerik:RadScheduleView.ViewDefinitions>
</telerik:RadScheduleView>

in code behind (loaded event):

        Dim appointment As IAppointment = ScheduleView.CreateNew()
        If appointment IsNot Nothing Then
            appointment.Start = DateTime.Now
            appointment.End = DateTime.Now.AddHours(1)
            appointment.Subject = "New appointment"
            ScheduleView.Commit()
        End If

[Kenneth]

OK, a duh moment.

ScheduleView.AppointmentsSource = New ObservableCollection(Of Appointment)

That is, Appointment not IAppointment.