(Hybrid Smart Client) RSS Media Player

<Window x:Name="mainwnd" x:Class="RSSVideoPlayer.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:RSSVideoPlayer"
    xmlns:UC="clr-namespace:RSSVideoPlayer.MediaElementControl"
    Title="WPF Media Player"  Height="457" Width="603">
    <Window.Resources>
        <ResourceDictionary Source="MainWindowResources.xaml"/>
    </Window.Resources>
        <Window.Background>
        <RadialGradientBrush>
            <GradientStop x:Name="Offset1" Offset="0" Color="Black"/>
            <GradientStop x:Name="Offset2" Offset="2" Color="Gray"/>
        </RadialGradientBrush>
    </Window.Background>
    <Grid>
        <DockPanel Name="dockPanel1" >
           <Menu DockPanel.Dock="Top" Height="20" Margin="0,0,0,5">
                <Menu.Background>
                    <LinearGradientBrush>
                        <GradientStop Offset="1" Color="Black"/>
                        <GradientStop Offset="0" Color="LightGray"/>
                    </LinearGradientBrush>
                </Menu.Background>
                <MenuItem Header="Exit" Command="{Binding cmdExit}"/>
               <MenuItem Header="Settings"/>
                <MenuItem Header="Windows">
                    <MenuItem Header="Library" Command="{Binding cmdLibrary}"></MenuItem>
                    <MenuItem Header="Video RSS" Command="{Binding cmdRSS}"></MenuItem>
                </MenuItem>
            </Menu>
           
            <Expander  IsExpanded="{Binding Expanded}"  DockPanel.Dock="Bottom" ExpandDirection="Up" Header="Media" Background="Black" Foreground="White">
                <DockPanel>
                    <TabControl  
              IsSynchronizedWithCurrentItem="True" 
              ItemsSource="{Binding Tabs}" 
              TabStripPlacement="Top" 
              ItemTemplate="{StaticResource ClosableTabItemTemplate}"
              Margin="4"
             >
                        <TabControl.Background>
                            <LinearGradientBrush>
                                <GradientStop Offset="2" Color="Black"/>
                                <GradientStop Offset="0" Color="LightGray"/>
                            </LinearGradientBrush>
                        </TabControl.Background>
                    </TabControl>
                </DockPanel>
            </Expander>
            <UC:MyMediaControl MyMediaSource="{Binding ElementName=mainwnd,Path=DataContext.Source}"></UC:MyMediaControl>
        </DockPanel>
    </Grid>
</Window>