<Window x:Class="WpfApp1.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"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.Resources>
        <Style TargetType="MenuItem">
            <Setter Property="Foreground" Value="Red" />
        </Style>
    </Window.Resources>
    <DockPanel>
        <Menu DockPanel.Dock="Top">
            <MenuItem Header="_File">
                <MenuItem Header="_New" />
                <MenuItem Header="Parent">
                    <MenuItem Header="Nested"/>
                </MenuItem>
            </MenuItem>
        </Menu>
    </DockPanel>
</Window>