title: becomeFirstResponder seems to work only 1st time for shake gesture
body: <p>I'm making my app shake-gesture-compatible by doing this in my UIViewController:</p>
  
  <pre><code>- (void)viewWillAppear:(BOOL)animated
  {
      [self.view becomeFirstResponder];
      [super viewWillAppear:animated];
  }
  </code></pre>
  
  <p>The problem is that when I flip to another view (I'm using the "Utility App" template which has a flipside view and a root view controller to manage them both) the shake gesture ceases to work when I come back.</p>
  
  <p>I see that the <code>viewWillAppear</code> method is called, it just doesn't seem that the view regains first responder status the second time around.</p>