title: What's the right UIControlState for the UIButton being pressed?
body: <p>I'm customizing the <code>UIButton</code> programmatically here:</p>
  
  <pre><code>button = [UIButton buttonWithType:UIButtonTypeCustom];
          [button setSelected:YES];
          button.frame = CGRectMake(x, y, width, height);
          [button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
          [button setTitleColor:[UIColor blueColor] forState:UIControlStateSelected];
          [button setTitle:@"Button Title" forState:UIControlStateNormal];
          [button addTarget:self action:@selector(buttonAction:) forControlEvents:UIControlEventTouchUpInside];
          [button setBackgroundImage:[UIImage imageNamed:@"button.png"] forState:UIControlStateNormal];
          [button setBackgroundImage:[UIImage imageNamed:@"buttonActive.png"] forState:UIControlStateSelected];
          [button setBackgroundImage:[UIImage imageNamed:@"buttonActive.png"] forState:UIControlStateHighlighted];
          [button setBackgroundImage:[UIImage imageNamed:@"buttonActive.png"] forState:UIControlStateDisabled];
  </code></pre>
  
  <p>The issue is if I'm holding down the image background image disappears until I'm releasing it...</p>