EditAppointmentDialogStyle and Catigories

[Zhenya Popkin]

Hi,
I am trying create a custom DialogWindow with my catigories. But When the window opening Combobox categories is clear.
My code is main window is

namespace Calendar
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        AppintmentViewModel main;

        public MainWindow()
        {
            InitializeComponent();
            main = new AppintmentViewModel();
            this.DataContext = main;
        }
    }


    internal class AppintmentViewModel : BaseViewModel
    {
        private ObservableCollection<Category> _Categories;
        ObservableCollection<Task> _Appointments;

        public AppintmentViewModel()
        {
            _Appointments = new ObservableCollection<Task>()
            {

                new Task(){Subject="April",Start =DateTime.Today,End =DateTime.Today.AddHours(4)},
            };
            _Categories = new ObservableCollection<Category>()
            {

                new Category(){ CategoryBrush= Brushes.Red, CategoryName="Red"},
                new Category(){CategoryBrush= Brushes.Blue, CategoryName="Blue"}
            };
        }
        public ObservableCollection<Task> Appointments
        {
            get
            {
                return _Appointments;
            }
            set
            {
                _Appointments = value;
                OnPropertyChanged("Appointments");
            }
        }

        public ObservableCollection<Category> Categories
        {
            get
            {
                return _Categories;
            }
            set
            {
                _Categories = value;
                OnPropertyChanged("Categories");
            }
        }

    }

    public class Task : Appointment
    {

        public override IAppointment Copy()
        {

            var newAppointment = new Task();

            newAppointment.CopyFrom(this);

            return newAppointment;

        }



        public override void CopyFrom(IAppointment other)
        {

            var task = other as Task;

            base.CopyFrom(other);

        }
    }
}

and XAML

<Window x:Class="Calendar.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        xmlns:schedule="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.ScheduleView"
        xmlns:scheduleView="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.ScheduleView"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <ControlTemplate x:Key="EditAppointmentTemplate" TargetType="scheduleView:SchedulerDialog">
            <Grid IsSharedSizeScope="True">
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="*" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>

                <telerik:RadToolBar x:Name="AppointmentToolbar"  BorderThickness="0 0 0 1" FocusManager.IsFocusScope="False"
                 GripVisibility="Collapsed" Grid.Row="0" Margin="-1 0 -1 3">
                    <telerik:RadButton x:Name="EditRecurrenceButton" Command="scheduleView:RadScheduleViewCommands.EditRecurrenceRule">
                        <ToolTipService.ToolTip>
                            <ToolTip telerik:LocalizationManager.ResourceKey="EditRecurrence"  />
                        </ToolTipService.ToolTip>
                        <TextBlock Margin="6 0" telerik:LocalizationManager.ResourceKey="EditRecurrence" />
                    </telerik:RadButton>
                    <telerik:RadToolBarSeparator />
                    <telerik:RadComboBox x:Name="PART_Categories" Margin="2 1" Width="130"  ItemsSource="{Binding ElementName=ScheduleView, Path=CategoriesSource}" DisplayMemberPath="{Binding CategoryName}" />

                </telerik:RadToolBar>
            </Grid>
        </ControlTemplate>
        <Style x:Key="EditAppointmentDialogStyle" TargetType="scheduleView:SchedulerDialog">
            <Setter Property="Width" Value="560" />
            <Setter Property="IsTabStop" Value="False" />

            <Setter Property="SnapsToDevicePixels" Value="True" />

            <Setter Property="Template" Value="{StaticResource EditAppointmentTemplate}" />
        </Style>

    </Window.Resources>
    <Grid>
        <telerik:RadScheduleView AppointmentsSource="{Binding Appointments}" EditAppointmentDialogStyle="{StaticResource EditAppointmentDialogStyle}"
                                      FirstVisibleTime="12:00" x:Name="ScheduleView" CategoriesSource="{Binding Categories}"
                                      ActiveViewDefinitionIndex="1">
            <telerik:RadScheduleView.ViewDefinitions>
                <telerik:DayViewDefinition />
                <telerik:WeekViewDefinition />
                <telerik:MonthViewDefinition />
                <telerik:TimelineViewDefinition DayStartTime="00:00" />
            </telerik:RadScheduleView.ViewDefinitions>
        </telerik:RadScheduleView>
    </Grid>
</Window>

If I removeEditAppointmentDialogStyle, I see mian Catigories. Can you help me?
Thank's