         var explicitViewportH:Number = viewportUIC ? viewportUIC.explicitHeight : NaN;
         
         // Decide which scrollbars will be visible based on the viewport's content size
+        // See the method doc above for more information.
+
         var showHSB:Boolean = false;
         var hAuto:Boolean = false; 
         switch(scroller.horizontalScrollPolicy) {

        var vsb:ScrollBar = scroller.verticalScrollBar;
        var minViewportInset:Number = scroller.minViewportInset;
        
        var oldShowHSB:Boolean = hsb && hsb.visible;
        var oldShowVSB:Boolean = vsb && vsb.visible;
        

            measuredH += viewportElt.getPreferredBoundsHeight();
        }
        
        // If the viewport's explicit size is set, then 
        // include that in the scroller's minimum size
        var viewportUIC:IUIComponent = viewport as IUIComponent;
        var explicitViewportW:Number = viewportUIC ? viewportUIC.explicitWidth : NaN;
        var explicitViewportH:Number = viewportUIC ? viewportUIC.explicitHeight : NaN;
        if (!isNaN(explicitViewportW)) minW += explicitViewportW;
        if (!isNaN(explicitViewportH)) minH += explicitViewportH;
        
        var hsb:ScrollBar = scroller.horizontalScrollBar;
        var showHSB:Boolean = false;
        switch(scroller.horizontalScrollPolicy) 
        {
            case ScrollPolicy.ON: 
                if (hsb) showHSB = true; 
                break;
            case ScrollPolicy.AUTO: 
                if (hsb) showHSB = hsb.visible;
                break;
        } 

        var vsb:ScrollBar = scroller.verticalScrollBar;
        var showVSB:Boolean = false;
        switch(scroller.verticalScrollPolicy) 
        {
           case ScrollPolicy.ON: 
                if (vsb) showVSB = true; 
                break;
            case ScrollPolicy.AUTO: 
                if (vsb) showVSB = vsb.visible;
                break;
        }
        
