title: CALayer delegate method drawLayer not getting called
body: <p>My object a sub class of NSObject has  CALayer instance variable. I use it for drawing and caching content with its delegate set to my object.</p>
  
  <p>But for some reason <code>drawLayer:inContext:</code> method NEVER gets called.  Whereas <code>actionForLayer:forKey:</code> delegate method does get called implying the delegate is getting set properly with <code>layer.delegate = self</code> in the object's init method.</p>
  
  <p>Any suggestions on what is preventing my layer drawing method <code>drawLayer:inContext:</code> from getting called ?</p>
  
  <p>I am called the <code>[layer setNeedDisplay]</code> often. So I guess it is some fundamental error. </p>