Bug Behavior System.Windows.Media.Pen

MainWindow.xaml

<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:local="clr-namespace:WpfApp1"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Title="MainWindow"
    Width="800"
    Height="450"
    mc:Ignorable="d">
    <Grid Name="theGrid">
        <Button
            Width="100"
            Height="40"
            Click="Button_Click">
            Change Pattern
        </Button>
        <TextBlock Name="dashText" Width="300" d:Text="test" TextAlignment="Center" VerticalAlignment="Center" Margin="0,-70,0,0"/>

    </Grid>
</Window>

MainWindow.xaml.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 WpfApp1
{

    public class LineVisual : DrawingVisual
    {

    }




    public class LineElement : UIElement
    {
        public static Pen Pen { get; set; } = new Pen(new SolidColorBrush(Colors.Black), 3);

        private LineVisual LineVisual;
        private LineGeometry lg { get; init; }

        protected override Visual GetVisualChild(int index) => LineVisual;

        protected override int VisualChildrenCount => 1;


        public LineElement(Point start, Point end)
        {

            lg = new LineGeometry(start, end);

            LineVisual = new LineVisual();
            DrawingContext dc = LineVisual.RenderOpen();
            dc.DrawGeometry(null, Pen, lg);
            dc.Close();

        }

    }








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

            

        }
        

        private int _counter = 0;
        private int Counter
        {
            get
            {
                return _counter;
            }
            set
            {
                if(value == 5)
                {
                    _counter = 0;   
                }
                else
                {
                    _counter = value;
                }
            }
        }

        private double Yval { get; set; } = 20;


        private void Button_Click(object sender, RoutedEventArgs e)
        {
            switch (Counter)
            {
                case 0:
                    LineElement l1 = new LineElement(new Point(10, Yval), new Point(200, Yval));
                    theGrid.Children.Add(l1);
                    LineElement.Pen.DashStyle = DashStyles.Solid;
                    dashText.Text = LineElement.Pen.DashStyle.Dashes.ToString();
                    Yval += 20;
                    Counter++;
                    break;
                case 1:
                    LineElement.Pen.DashStyle = DashStyles.Dash;
                    dashText.Text = LineElement.Pen.DashStyle.Dashes.ToString();
                    LineElement l2 = new LineElement(new Point(10,Yval), new Point(200,Yval));
                    theGrid.Children.Add(l2);
                    Yval += 20;
                    Counter++;
                    break;
                case 2:
                    LineElement.Pen.DashStyle = DashStyles.Dot;
                    dashText.Text = LineElement.Pen.DashStyle.Dashes.ToString();
                    LineElement l3 = new LineElement(new Point(10, Yval), new Point(200, Yval));
                    theGrid.Children.Add(l3);
                    Yval += 20;
                    Counter++;
                    break;
                case 3:
                    LineElement.Pen.DashStyle = DashStyles.DashDot;
                    dashText.Text = LineElement.Pen.DashStyle.Dashes.ToString();
                    LineElement l4 = new LineElement(new Point(10, Yval), new Point(200, Yval));
                    theGrid.Children.Add(l4);
                    Yval += 20;
                    Counter++;
                    break;
                case 4:
                    LineElement.Pen.DashStyle = DashStyles.DashDotDot;
                    dashText.Text = LineElement.Pen.DashStyle.Dashes.ToString();

                    LineElement l5 = new LineElement(new Point(10, Yval), new Point(200, Yval));
                    theGrid.Children.Add(l5);
                    Yval += 20;
                    Counter++;
                    break;

                default:
                    throw new ArgumentOutOfRangeException();
            }

        }
    }
}