To reproduce:

Private Sub cbo1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As Telerik.WinControls.UI.Data.PositionChangedEventArgs) Handles cbo1.SelectedIndexChanged
    If e.Position <> -1 Then
        cbo1.Items.Clear()
        For i = 1 To 10
            cbo1.Items.Add(i.ToString)
        Next i

    End If

    cbo1.SelectedIndex = 4

End Sub