<ListBox Focusable="True" HorizontalContentAlignment="Stretch" Name="listBoxTasks" Grid.Row="1" Margin="4">
            <ListBox.Resources>
                <SolidColorBrush Color="Transparent" x:Key ="{x:Static SystemColors.HighlightBrushKey}" />
            </ListBox.Resources>
        </ListBox>

<UserControl x:Class="TaskTracker.View.Elements.TaskElement"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             d:DesignHeight="67" d:DesignWidth="437" Margin="2">
    <Border BorderThickness="2" Grid.ColumnSpan="3" Name="brdOuter" CornerRadius="6" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Padding="5" 
            BorderBrush="SteelBlue" >
        <TextBlock Name="tbInfo" Text="TextBlock" HorizontalAlignment="Center" VerticalAlignment="Center" Foreground="Black" />
    </Border>
</UserControl>

            <ListBox.ItemContainerStyle>
                <Style>
                    <Style.Triggers>
                        <Trigger Property="ListBoxItem.IsSelected" Value="True">
                            <Setter Property="TextBlock.Foreground" Value="Green"/>
                            <Setter Property="Border.Background" Value="LightSteelBlue"/>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </ListBox.ItemContainerStyle>