title: What happens to pending messages for a window that has been destroyed?
body: <p>What happens when a window is destroyed while there are still messages pending for it?</p>
  
  <p>Consider the following scenario:</p>
  
  <p>There are three threads, A, B, and C.  Thread C owns a window.</p>
  
  <p>Threads A and B use <code>SendMessage</code> to post messages to the window.  The message from A arrives first.  While C is processing the message from A, it destroys its window using <code>DestroyWindow</code>.</p>
  
  <p>What happens to the message from thread B?  Does the call by thread B to <code>SendMessage</code> return?</p>
  
  <p>How does this work internally?</p>