 /**
  *  Name of the class to use as the skin for the thumb of the scroll bar.
  *  
- *  @default mx.skins.halo.ScrollThumbSkin
+ *  <p>The default skin class is based on the theme. For example, with the Halo theme,
+ *  the default skin class is <code>mx.skins.halo.ScrollThumbSkin</code>. For the Spark theme, the default skin
+ *  class is <code>mx.skins.spark.ScrollBarThumbSkin</code>.</p>
  *  
  *  @langversion 3.0
  *  @playerversion Flash 9

 *  Name of the class to use as the skin for the thumb of the scroll bar 
 *  when the mouse pointer is over the thumb. 
 * 
 *  @default mx.skins.halo.ScrollThumbSkin
 *  
 *  @langversion 3.0
 *  @playerversion Flash 9

 *  Name of the class to use as the skin for the down arrow button of the 
 *  scroll bar when the mouse pointer is over the arrow button. 
 * 
 *  <p>If you change the skin, either graphically or programmatically, 
 *  you should ensure that the new skin is the same height 
 *  (for horizontal ScrollBars) or width (for vertical ScrollBars) as the track.</p>
 *  
 *  <p>The default skin class is based on the theme. For example, with the Halo theme,
 *  the default skin class is <code>mx.skins.halo.ScrollArrowSkin</code>. For the Spark theme, the default skin
 *  class is <code>mx.skins.spark.ScrollBarDownButtonSkin</code>.</p>
 *  
 *  @langversion 3.0
 *  @playerversion Flash 9
