 
 /**
  *  The Scroller component displays a single scrollable component, 
- *  called a viewport, and a horizontal and vertical scrollbars. 
+ *  called a viewport, and horizontal and vertical scroll bars. 
  *  The viewport must implement the IViewport interface.
+ *
+ *  <p>The Spark Group, DataGroup, and RichEditableText components implement 
+ *  the IViewport interface and can be used as the children of the Scroller control,
+ *  as the following example shows:</p>
  * 
- *  <p>The scrollbars control the viewport's <code>horizontalScrollPosition</code> and
+ *  <pre>
+ *  &lt;s:Scroller&gt;
+ *       &lt;s:Group width="100" height="100"&gt; 
+ *          &lt;mx:Image width="300" height="400" 
+ *               source="&#64;Embed(source='assets/logo.jpg')"/&gt; 
+ *       &lt;/s:Group&gt;        
+ *  &lt;/s:Scroller&gt;</pre>     
+ *
+ *  <p>The size of the Image control is set larger than that of its parent Group container. 
+ *  By default, the child extends past the boundaries of the parent container. 
+ *  Rather than allow the child to extend past the boundaries of the parent container, 
+ *  the Scroller specifies to clip the child to the boundaries and display scroll bars.</p>
+ *
+ *  <p>For Spark containers that do not implement the IViewport interface, 
+ *  you can still use scroll bars. 
+ *  To add scroll bars, create a custom skin for the container that 
+ *  includes the Scroller control. </p>
+ * 
+ *  <p>The IViewport interface define a viewport for the components that implement it.
+ *  A viewport is a rectangular subset of the area of a container that you want to display, 
+ *  rather than displaying the entire container.
+ *  The scrollbars control the viewport's <code>horizontalScrollPosition</code> and
  *  <code>verticalScrollPosition</code> properties.
  *  Scrollbars make it possible to view the area defined by the viewport's 
  *  <code>contentWidth</code> and <code>contentHeight</code> properties.</p>
+ *
+ *  <p>You can combine scroll bars with explicit settings for the container's viewport. 
+ *  The viewport settings determine the initial position of the viewport, 
+ *  and then you can use the scroll bars to move it, as the following example shows: </p>
+ *  
+ *  <pre>
+ *  &lt;s:Scroller&gt;
+ *      &lt;s:Group width="100" height="100"
+ *          horizontalScrollPosition="50" verticalScrollPosition="50"&gt; 
+ *          &lt;mx:Image width="300" height="400" 
+ *              source="&#64;Embed(source='assets/logo.jpg')"/&gt; 
+ *      &lt;/s:Group&gt;                 
+ *  &lt;/s:Scroller&gt;</pre>
  * 
- *  <p>The scrollbars are displayed according to the vertical and horizontal scrollbar
+ *  <p>The scrollbars are displayed according to the vertical and horizontal scroll bar
  *  policy, which can be <code>auto</code>, <code>on</code>, or <code>off</code>.
  *  The <code>auto</code> policy means that the scrollbar will be visible and included
  *  in the layout when the viewport's content is larger than the viewport itself.</p>

    private var _measuredSizeIncludesScrollBars:Boolean = true;
    
    /**
     *  If true, the Scroller's measured size includes the space required for
     *  the visible scrollbars, otherwise the Scroller's measured size depends
     *  only on its viewport.
     * 
     *  <p>Components like TextArea, which "reflow" their contents to fit the
     *  available width or height may use this property to stabilize their
     *  measured size.  By default a TextArea's is defined by its widthInChars
     *  and heightInChars properties and in many applications it's preferable
     *  for the measured size to remain constant, event when scrollbars are displayed
     *  by the TextArea skin's Scroller.</p>
     * 
     *  <p>In components where the content does not reflow, like a typical List's

 *  /&gt;
 *  </pre>
 *  
 *  @see spark.core.IViewport
 *  @see spark.components.DataGroup
 *  @see spark.components.Group
 *  @see spark.components.RichEditableText
 *  @see spark.skins.spark.ScrollerSkin
 *
 *  @includeExample examples/ScrollerExample.mxml
 *  
 *  @langversion 3.0
 *  @playerversion Flash 10
 *  @playerversion AIR 1.5
