title: Close Popup when focus lost
body: <p>I have a popup containing a ListView. The ListView contains customer names. The popup is openen when a search bar is clicked. The user can enter text in the search bar (TextBox) and the Listview is filterd based on the input.</p>
  
  <p>I want to close the popup whenever it loses focus. However, the default "auto close" behaviour  <code>StaysOpen="False"</code> is no good, because it closes the popup everytime someone clicks on the search bar.</p>
  
  <p>How can I close the Popup always when it loses focus, except when the focus goes to the search bar?</p>