title: didMoveToWindow: How will this method be called?
body: <p>I spent time searching this without much success (including documentation), still left puzzled the <code>didMoveToWindow:</code> method.</p>
  
  <p>Using <code>didMoveToWindow:</code> in a stock view project template:  </p>
  
  <pre><code>-(void)didMoveToWindow{
  
      [super didMoveToWindow];
  
      // do something
  
  }
  </code></pre>
  
  <p>gives the following warning:</p>
  
  <blockquote>
    <p>Warning: 'UIViewController' may not respond to 'didMoveToWindow'</p>
  </blockquote>
  
  <p>It is not called on start up of view which is a surprise.<br>
  How will this method be called?</p>