PopupButton RoutedEvent not setting e.Handled=true correctly

public void CreatePopups()
{
    // Create a new window
    Window window = new Window { Width = 300, Height = 50 };

    // Set up the first level popup and hook up an event to notify us when it closes
    PopupButton level1 = new PopupButton { Label = "Click (Level 1)", VerticalAlignment = VerticalAlignment.Center };
    level1.PopupClosed += delegate { Debug.WriteLine("Level 1 Closed"); };

    // Set up the second level popup and hook up an event to notify us when it closes
    PopupButton level2 = new PopupButton { Label = "Click (Level 2)" };
    level2.PopupClosed += delegate { Debug.WriteLine("Level 2 Closed"); };

    // Nest the popups
    level1.PopupContent = level2;

    // Set some arbitrary content
    level2.PopupContent = new Button { Label = "Click the 'Level 2' button again" };

    window.Content = level1;

    // Show the window
    window.Show();
}