title: Why does System.Windows.MessageBox lag a WPF window?
body: <p>Consider the following code:</p>
  
  <pre><code>private void Window_Loaded(object sender, RoutedEventArgs e)
  {
      MessageBox.Show("MyMessage");
  }
  </code></pre>
  
  <p>If I am trying to display a message box after a WPF window has been loaded, when I run the application, the WPF window is displayed with a transparent background (only the non-client area is visible) and it takes 3-5 seconds until the message box appears. The WPF window returns to normal only after the message box has been closed.</p>
  
  <p>Is this normal? Does anyone else experience this?</p>
  
  <p><strong>EDIT: I have added a screenshot of how the window looks like:</strong></p>
  
  <p><img src="https://i.stack.imgur.com/jRnJo.png" alt="enter image description here"></p>