public class AutoScroll
{
// this method is specifically written for the Scroller component
// to use this on other scroller components will need modification or
// another method
public static function autoScroll(event:FocusEvent):void
{
var scroller : Scroller = event.currentTarget as Scroller;
var focusItem : DisplayObject = DisplayObject(scroller.focusManager.getFocus());

// if no scrollbar or focused item, nothing to do
if(scroller.verticalScrollBar && focusItem)
{
// is the current focus item inside our container?
if( focusItem == scroller || !scroller.contains(focusItem) )
{
return;
}

// find the focusItem’s y coord in the scrolled container
// by summing the y offsets of the item and all parent containers in the tree
// between the target and the scrolled container
var focusTopEdge : int = focusItem.y;
var thisItem : DisplayObjectContainer = focusItem.parent;

while(thisItem != scroller)
{
focusTopEdge += thisItem.y;
thisItem = thisItem.parent;
}

var focusBottomEdge : int = focusTopEdge + focusItem.height;
var scrollbarRange : int = scroller.verticalScrollBar.maxHeight;
var visibleWindowHeight : int = scroller.height;
var lastVisibleY:int = visibleWindowHeight + scroller.viewport.verticalScrollPosition;

if(scroller.horizontalScrollBar)
{
// remove the horiz scrollbar height from lastVisibleY
lastVisibleY -= scroller.horizontalScrollBar.height;
}

if( focusTopEdge == scroller.viewport.verticalScrollPosition )
{
//trace( “Bar not moved, already at top edge of focus item.” );
}
else if( focusTopEdge 0 )
{
var newPos : int = Math.min(scrollbarRange, scroller.viewport.verticalScrollPosition + (focusBottomEdge-lastVisibleY));
scroller.viewport.verticalScrollPosition = newPos;
//trace( “Moved bar down to ” + newPos );
}
else
{
//trace( “Bar not moved.” );;
}
}
}
}

Thanks this code.

What were you expecting?