title: My presentation layer does not match my model layer even though I have no animations
body: <p>On iPhone I have a <code>CALayer</code> that I animate via Core Animation.  Then at some point I change view controllers.  I then return to the view controller with the <code>CALayer</code> and in <code>viewWillAppear:</code> I set the frame and position properties on my layer to move it back to its starting point.</p>
  
  <p>Setting these properties changes the model layer but the presentation layer still has the old values and its presentation layer does not update until the next animation I play.</p>
  
  <p>In the CA Programming guide it says : </p>
  
  <blockquote>
    <p>"You can query an instance of CALayer for its corresponding
    presentation layer while an animation transaction is in process."</p>
  </blockquote>
  
  <p>Which, to me, implies that the presentation layer should only be different from the model layer during an animation.  But there are no animations currently running.  I even used <code>kCATransactionDisableActions</code> to ensure that when I set the position property an implicit animation is not started.</p>
  
  <p>Does anyone know why my presentation and model layers are out of sync?</p>
  
  <p>Thanks.</p>