title: What does userInteractionEnabled = NO mean and how does it work?
body: <p>Cocos 2d-iphone 3.0. I am using this code to detect whether a single sprite is touched</p>
  <pre><code>-(void) touchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
    
      CGPoint location = [touch locationInView: [touch view]];
      CGPoint convertedlocation = [[CCDirector sharedDirector] convertToGL: location];
      CGPoint convertedNodeSpacePoint = [self convertToNodeSpace:convertedlocation];
      
      if (CGRectContainsPoint([_sprite boundingBox],convertedNodeSpacePoint)) 
      {
          // Remove sprite 
      }
  }
  </code></pre>
  <p>I have some code inside that should remove some other sprites from parent. Logically, when <code>_sprite</code></p>
  <p>is touched second time, application will crash, because other sprites'v been already removed.</p>
  <p>I was trying to make <code>_sprite</code> untouchable using  <code>_sprite.userInteractionEnabled = NO;</code>, but this has no effect.</p>
  <p>What does <code>userInteractionEnabled</code> mean exactly and how would one use this to facilitate touch detection on sprites.</p>
  <p>What is the optimal way of handling touches on sprites in my scene?</p>