prs/prs.desktop/Panels/Products/Kits/KitPanel.xaml

<UserControl x:Class="PRSDesktop.KitPanel"
             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"
             xmlns:local="clr-namespace:PRSDesktop"
             mc:Ignorable="d"
             d:DesignHeight="450" d:DesignWidth="800">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="0.3*" />
            <ColumnDefinition Width="0.7*" />
        </Grid.ColumnDefinitions>

        <DockPanel Grid.Row="0" Grid.Column="0">
            <Border CornerRadius="5,5,0,0" BorderBrush="Gray" BorderThickness="0.75" Background="WhiteSmoke"
                    DockPanel.Dock="Top">
                <Label Content="Available Kits" HorizontalContentAlignment="Center" />
            </Border>
            <local:KitGrid x:Name="Kits" Margin="0,2,0,0" DockPanel.Dock="Top" />
        </DockPanel>

        <DockPanel Grid.Column="1" Grid.Row="0" Margin="2,0,0,0">
            <Border CornerRadius="5,5,0,0" BorderBrush="Gray" BorderThickness="0.75" Background="WhiteSmoke"
                    DockPanel.Dock="Top">
                <Label Content="Kit Components" HorizontalContentAlignment="Center" DockPanel.Dock="Top" />
            </Border>
            <local:KitProductGrid x:Name="Products" Margin="0,2,0,0" DockPanel.Dock="Top" />
        </DockPanel>

    </Grid>
</UserControl>