WPF this.DragMove() DropShadowEffect

//xaml
<Window x:Class="WpfApp367.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:WpfApp367"
        mc:Ignorable="d"
        AllowsTransparency="True"
        WindowStyle="None"
        Background="Transparent"
        MouseLeftButtonDown="Window_MouseLeftButtonDown"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Ellipse Fill="Red" Opacity="0.5"
                 Margin="20">
            <Ellipse.Effect>
                <DropShadowEffect/>
            </Ellipse.Effect>
        </Ellipse>
        <Button Margin="100" Click="Button_Click">Close</Button>
    </Grid>
</Window>


//cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp367
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Window_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            this.DragMove();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            this.Close();
        }
    }
}