title: When should I use engine.getTouchOptions().setRunOnUpdateThread(true);
body: <p>I am looking at many of the andengine examples, and I am trying to understand when I need to use "getTouchOptions().setRunOnUpdateThread(true)". I understand that this might be helpful when a touch event triggers the removal of a sprite or entity. But why is is there in "PhysicsExample"</p>
  
  <pre class="lang-java prettyprint-override"><code>public Engine onLoadEngine() {
      Toast.makeText(this, "Touch the screen to add objects.", Toast.LENGTH_LONG).show();
      final Camera camera = new Camera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT);
      final EngineOptions engineOptions = new EngineOptions(true, ScreenOrientation.LANDSCAPE, new RatioResolutionPolicy(CAMERA_WIDTH, CAMERA_HEIGHT), camera);
      engineOptions.getTouchOptions().setRunOnUpdateThread(true);
      return new Engine(engineOptions);
  }
  </code></pre>
  
  <p>Do I need to make sure I only add bodies un the update thread because of Box2D? What iw ould like is to have a good understanding of that engine feature, and when to use it, and when I should not.</p>