<Window x:Class="SimpleWPF.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">
    <DockPanel>
          <Menu x:Name="menuMain" DockPanel.Dock="Top" Background="Bisque">
            <MenuItem Header="Info" Background="Chocolate">
                <MenuItem Header="One..." HorizontalAlignment="Left" Width="140" Background="DarkOliveGreen"/>
                <MenuItem Header="Two..." HorizontalAlignment="Left" Width="140"/>
                <Separator HorizontalAlignment="Left" Width="140"/>
                <MenuItem Header="Three..." HorizontalAlignment="Left" Width="140"/>
            </MenuItem>            
        </Menu>
    </DockPanel>
</Window>

/// <summary>
    /// Логика взаимодействия для MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }