contentPresenterControl.xaml

<UserControl
	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
	xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
	xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
	xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
	mc:Ignorable="d"
	x:Class="myRequirements.contentPresenterControl"
	d:DesignWidth="66" d:DesignHeight="16">
                <Grid Width="Auto">
			<Grid.RowDefinitions>
				<RowDefinition Height="Auto" MinHeight="10"/>
				<RowDefinition Height="Auto"/>
			</Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="40"/>
                    <ColumnDefinition Width="450"/>
                </Grid.ColumnDefinitions>

                <!--<Button x:Name="ListBoxExpander" Click="ListBoxExpander_Click" Grid.RowSpan="1" HorizontalAlignment="Center" VerticalAlignment="Center" Width="15" Height="15" Margin="0,0,0,0"/>-->
                <TextBlock  VerticalAlignment="Stretch" Grid.Column="2" TextWrapping="Wrap"  HorizontalAlignment="Stretch" Margin="10,10,10,10" Text="test" />
                <ListBox x:Name="PrivateRequirementListBoxChild"  SelectionChanged="mySecurityRequirementListBox_SelectionChanged" Style="{StaticResource ListboxBackground}" Margin="10,0,0,0" Grid.ColumnSpan="1" Grid.Row="1"  Grid.Column="1" Visibility="Collapsed">
                    <ListBox.ItemContainerStyle>
                        <Style TargetType="ListBoxItem">

                            <Setter Property="Background">
                                <Setter.Value>
                                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0" >
                                        <GradientStop Color="#0000F500" Offset="1"/>
                                        <GradientStop Color="#FFFFFFFF" Offset="0"/>
                                    </LinearGradientBrush>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </ListBox.ItemContainerStyle>

                </ListBox>
		</Grid>
</UserControl>