Following example shows how to setup vertical layout in spark application tag

<?xml version="1.0" encoding="utf-8"?>
<s:Application	 xmlns:fx="http://ns.adobe.com/mxml/2009"
   		 xmlns:mx="library://ns.adobe.com/flex/mx"
   		 xmlns:s="library://ns.adobe.com/flex/spark"> 

        <s:layout>
            <s:VerticalLayout
                paddingLeft="5" paddingRight="5"
                paddingTop="5" paddingBottom="5"/>
        </s:layout>

        <s:Button label="Sample1"/>
        <s:Button label="Sample2"/>
        <s:Button label="Sample3"/>
        <s:Button label="Sample4"/>

</s:Application>

Tags: HorizontalLayout, layout, paddingBottom, paddingLeft, paddingRight, paddingTop