<Window x:Class="Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="720" Width="1048">
<!--Top Grid-->
    <Grid Height="45" VerticalAlignment="Top">
 
        <Grid Height="612" Margin="0,0,0,-610" Name="Grid1" _
          VerticalAlignment="Bottom">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <Label Background="Yellow" Grid.Column="0"/>
            <GridSplitter Grid.Column="0" Width="10" />
            <Label Background="Green" Grid.Column="1"/>
            <Grid Name="Grid2" Background="Black" Grid.Column="1" >
                <Grid.RowDefinitions>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="10"/>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>
                <Label Background="Aqua" Grid.Row="0"/>
                <GridSplitter Grid.Row="1" HorizontalAlignment="Stretch"/>
                <Label Background="HotPink" Grid.Row="3" />
 
            </Grid>
 
        </Grid>
    </Grid>
 
</Window>