<s:ComboBox 	
    xmlns:fx="http://ns.adobe.com/mxml/2009" 
    xmlns:s="library://ns.adobe.com/flex/spark"
    height="24" width="147">    
    
    <s:dataProvider>
    	<s:ArrayCollection>
    		<fx:String>Very long item name to see how it will be displayed in the DropDownList</fx:String>
    		<fx:String>Short Item</fx:String>
    		<fx:String>Select One</fx:String>
		</s:ArrayCollection>
	</s:dataProvider>
	
</s:ComboBox>