aistudio-wpf-diagram/AIStudio.Wpf.DiagramDesigner.Demo/MainWindow.xaml

<Window x:Class="AIStudio.Wpf.DiagramDesigner.Demo.MainWindow"
        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"
        xmlns:local="clr-namespace:AIStudio.Wpf.DiagramDesigner.Demo"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" MinWidth="100" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <ListBox x:Name="listbox" SelectionChanged="ListBox_SelectionChanged">

        </ListBox>
        <GridSplitter Width="2"
                      VerticalAlignment="Stretch" />
        <ContentControl x:Name="ContentControl"
                        Grid.Column="1"
                        Margin="0" />
    </Grid>
</Window>