Setting a roll over open delay on a Spark DropDownList control in Flex 4

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2010/02/03/setting-a-roll-over-open-delay-on-a-spark-dropdownlist-control-in-flex-4/ -->
<s:Application name="Spark_DropDownList_dropDownController_rollOverOpenDelay_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/mx"
        xmlns:local="*">
    <s:layout>
        <s:VerticalLayout horizontalAlign="center" paddingTop="20" />
    </s:layout>
    <s:controlBarContent>
        <mx:Form>
            <mx:FormItem label="rollOverOpenDelay:" direction="horizontal">
                <s:HSlider id="sl"
                        minimum="100" maximum="1500"
                        value="200"
                        change="init();" />
                <s:Label text="{sl.value} ms" />
            </mx:FormItem>
        </mx:Form>
    </s:controlBarContent>
 
    <fx:Script>
        <![CDATA[
            import spark.components.supportClasses.DropDownController;
 
            private function init():void {
                var con:DropDownController = dropper.controller;
                con.rollOverOpenDelay = sl.value;
            }
        ]]>
    </fx:Script>
 
    <local:MyDropDownList id="dropper"
            prompt="Roll over to open..."
            width="200"
            creationComplete="init();">
        <local:dataProvider>
            <s:ArrayList source="[Red,Orange,Yellow,Green,Blue,Purple]" />
        </local:dataProvider>
    </local:MyDropDownList>
 
</s:Application>

/** http://blog.flexexamples.com/2010/02/03/setting-a-roll-over-open-delay-on-a-spark-dropdownlist-control-in-flex-4/ */
package {
    import spark.components.DropDownList;
    import spark.components.supportClasses.DropDownController;
 
    public class MyDropDownList extends DropDownList {
        public function MyDropDownList() {
            super();
        }
 
        public function get controller():DropDownController {
            return super.dropDownController;
        }
 
        public function set controller(value:DropDownController):void {
            super.dropDownController = value;
        }
    }
}