title: Override sublayout on a Screen or VerticalFieldManager
body: <p>I am adding a VerticalFieldManager to a screen. I'm  painting a background image and to remove whitespace at the bottom of screen when user scrolls down im overriding sublayout in my verticalfieldmanager like so:</p>
  
  <pre><code>protected void sublayout( int maxWidth, int maxHeight ) {
      super.sublayout( maxWidth, maxHeight );
      setExtent(maxWidth,Constants.BACKGROUND_IMAGE.getHeight());  
  }
  </code></pre>
  
  <p>This doesn't work -- white space appears at the bottom of the screen when the user scrolls down.  I thought overriding sublayout, using the same code, on the screen object would take precedence over the VerticalFieldManager, which is a child of the screen.  </p>