<Window x:Class="Layout.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="25"></RowDefinition>
                <RowDefinition></RowDefinition>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="150"></ColumnDefinition>
                <ColumnDefinition Width="auto"></ColumnDefinition>
                <ColumnDefinition></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <TextBox Grid.ColumnSpan="3" BorderBrush="Black"></TextBox>
            <TextBox Grid.Row="1" BorderBrush="Black"></TextBox>
            <GridSplitter Grid.Row="1" Grid.Column="1"
                          VerticalAlignment="Stretch"
                          HorizontalAlignment="Center"
                          Width="5"
                          Background="Gray"
                          ShowsPreview="True"></GridSplitter>
            <TextBox Grid.Row="1" Grid.Column="2" BorderBrush="Black"></TextBox>
        </Grid>
    </Grid>
</Window>