Occurs when the IsOpen property changes to false.
public event EventHandler Closed
<object Closed="EventHandler" .../>
A Popup is opened and closed by toggling the IsOpen property.
The following example shows how to define an event handler for the Closed event.
private void PopupClosing(object sender, EventArgs e)
//Code to execute when Popup closes
<TextBlock Background="Yellow">Popup Text</TextBlock>