title: Custom UISlider images not working quite right
body: <p>With this code:</p>
  
  <pre><code>UISlider *slider = [[UISlider alloc]initWithFrame:sliderFrame];
      [slider setThumbImage:[UIImage imageNamed:@"sliderThumb"] forState:UIControlStateNormal];
      UIImage *sliderLeftTrackImage = [[UIImage imageNamed: @"sliderMin"] stretchableImageWithLeftCapWidth: 9 topCapHeight: 0];
      UIImage *sliderRightTrackImage = [[UIImage imageNamed: @"sliderMax"] stretchableImageWithLeftCapWidth: 9 topCapHeight: 0];
      [slider setMinimumTrackImage: sliderLeftTrackImage forState: UIControlStateNormal];
      [slider setMaximumTrackImage: sliderRightTrackImage forState: UIControlStateNormal];
  </code></pre>
  
  <p>sliderMin and sliderMax images are both 210x34 (same size as the slider frame). sliderMin is blue and sliderMax is red. When the slider is all the way to the left, I correctly see the red bar. However, after sliding the thumb a few pixels to the right, the entire bar turns blue (the sliderMin image). Obviously I should only see the blue bar on the left of the slider. What am I doing wrong?</p>