title: deactivating/activating a UGUI button leaves it in pressed state
body: <p>I have a button with "animation" transition type. When I click it, I call <code>SetActive(false)</code> on its gameObject. Then, by clicking another button, I call <code>SetActive(true)</code> to activate the deactivated button, but the animation does not reset: it's still in pressed state (like it was when I deactivated it, because I was pressing it), and it does not back to idle state. </p>
  
  <p>EDIT: I realized I have not set the sprite for "normal" state in the animation. But I don't understand why before deactivate/activate, the button is showing default sprite for idle state, and after deactivate/activate, is showing pressed sprite for idle state. </p>