WPF PopUp Control with OpenFileDialog

<Window x:Class="WpfApplication2.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300" MouseEnter="Window_MouseEnter">
    <Grid>
      <Popup x:Name="PopupTest" AllowsTransparency="True" Opened="PopupTest_Opened" MouseDown="PopupTest_MouseDown">
         <Viewbox VerticalAlignment="Top">
            <TextBlock Text="WWW">

            </TextBlock>
         </Viewbox>
      </Popup>
   </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
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;
using Microsoft.Win32;

namespace WpfApplication2
{
   /// <summary>
   /// Interaction logic for Window1.xaml
   /// </summary>
   public partial class Window1 : Window
   {
      public Window1()
      {
         InitializeComponent();
      }

      private void Window_MouseEnter(object sender, MouseEventArgs e)
      {
         PopupTest.Placement = System.Windows.Controls.Primitives.PlacementMode.Mouse;
         PopupTest.StaysOpen = false;
         PopupTest.Height = 1000;
         PopupTest.Width = 500;
         PopupTest.IsOpen = true;
      }

      private void PopupTest_Opened(object sender, EventArgs e)
      {
         //var dialog = new OpenFileDialog();
         //dialog.ShowDialog();
      }

      private void PopupTest_MouseDown(object sender, MouseButtonEventArgs e)
      {
         var dialog = new OpenFileDialog();
         dialog.ShowDialog();
      }

   }
}