Super simple as3 VBox.

VBox.as

package com.wegoodhq.view.component.ui.layout
{	
	import flash.display.DisplayObject;

	public class VBox extends SelectableElement
	{
		private var _spacing:int;
		private var _currentY:int = 0;
		
		public function VBox(spacing:int = 0)
		{
			_spacing = spacing;
		}
		
		override public function addChild(child:DisplayObject) : DisplayObject
		{
			child.y = _currentY;
			_currentY += (child.height + _spacing);
			return super.addChild(child);
		}
	}
}