title: Window.Show() - How can I guarantee that window is on screen
body: <p>I have a WPF application rendering WPF content inside a Window.
  We call Window.Show() to put the content on screen.</p>
  
  <p>We use a StopWatch to measure elasped time with Start/Stop calls either side of the Show() call, and log out every time the Show is called.</p>
  
  <p>When I have my elapsed time, is this enough to guarantee that the Window is on screen, or is the GPU still putting the WPF content on the screen even though the Show call is complete? Is the ContentRendered a better event to listen to, or could this also complete before the content is on screen?</p>
  
  <p>Is anyone aware of any alternative methods of measuring when WPF content is truly on the user's screen?</p>