WPF

<ListBox x:Name="AheadListBox" 
         FontSize="20" 
         BorderBrush="Transparent" BorderThickness="0,0,0,0" 
         Background="Transparent" 
         ScrollViewer.VerticalScrollBarVisibility="Auto" 
         ScrollViewer.HorizontalScrollBarVisibility="Hidden">
    <ListBox.ItemTemplate>
	<DataTemplate>
 	    <Grid >
		<Grid.ColumnDefinitions>
		    <ColumnDefinition Width="Auto" />
		    <ColumnDefinition Width="*" />
		</Grid.ColumnDefinitions>
	        <Ellipse Grid.Column="0" Width="20" Height="20" 
                         VerticalAlignment="Top" 
                         HorizontalAlignment="Left" 
                         Margin="5,0,0,0">
		    <Ellipse.Fill>
			<RadialGradientBrush GradientOrigin=".5,.3">
			    <GradientStop Color="LightSteelBlue" Offset="0.05"/>
			    <GradientStop Color="DarkBlue" Offset="0.9"/>
			    <GradientStop Color="DarkBlue" Offset="1"/>
			</RadialGradientBrush>
		    </Ellipse.Fill>
		</Ellipse>

		<TextBlock Grid.Column="1" 
                           Text="Some really long text string to test the veracity of my XAML Layout. Of course, nothing works the first time where Silverlight is concerned" 
                           Margin="10,0,10,0" 
                           TextWrapping="Wrap" />

	    </Grid>
	</DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

internal ObservableCollection<INVCategory> GetCategoryList()
{
     DataLoadOptions dataLoadOptions = new DataLoadOptions();
     dataLoadOptions.LoadWith<INVCategory>(t => t.INVSubCategories);
     this.Context.LoadOptions = dataLoadOptions;

     var categories = from category in this.Context.INVCategories
                      orderby category.CatgeoryId descending
                      select category;
     return new ObservableCollection<INVCategory>(categories.ToList());
}

<ComboBox Grid.Column="1" Grid.Row="0" HorizontalAlignment="Stretch"                           VerticalAlignment="Stretch" Margin="0,2,10,2" TabIndex="0" x:Name="categoryComboBox"      
ItemsSource="{Binding CategoryList}" IsEditable="True" DisplayMemberPath="CategoryName"  SelectedValuePath="CatgeoryId" SelectedItem="{Binding CategoryList, Mode=TwoWay}" SelectedValue="{Binding Path=CurrentEntity.CategoryId, Mode=TwoWay}" >
</ComboBox>

<ComboBox Grid.Column="1" Grid.Row="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="0,2,10,2" TabIndex="1"
ItemsSource="{Binding SelectedItem, ElementName=categoryComboBox, Mode=OneWay}" 
DisplayMemberPath="SubCategoryName" SelectedValuePath="SubCategoryId"
SelectedItem="{Binding INVSubCategories, Mode=TwoWay}">
</ComboBox>

C:\My Source 2010\PHDWebsite\PHDWebsite\obj\Debug\MainPage.g.i.cs(62,42): error CS0234: The type or namespace name 'DockPanel' does not exist in the namespace 'System.Windows.Controls' (are you missing an assembly reference?)

xmlns:controlsToolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Toolkit"

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3245: Could not resolve this reference. Could not locate the assembly "System.Windows.Controls.Toolkit, Version=2.0.5.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors.