<? xml version="1.0" encoding="utf-8" ?>

<!--  http://blog.flexexamples.com/2007/11/29/using-the-itemdoubleclick-event-to-open-nodes-in-a-flex-tree-control/  -->

< mx:Application  xmlns:mx ="http://www.adobe.com/2006/mxml"

        layout ="horizontal"

        verticalAlign ="middle"

        backgroundColor ="white"

        creationComplete ="init();" >

     < mx:Script >

         <![CDATA[

            import mx.events.ListEvent;

            private function tree_itemDoubleClick(evt:ListEvent):void {

                var node:XML = tree.selectedItem as XML;

                var isOpen:Boolean = tree.isItemOpen(node);

                tree.expandItem(node, !isOpen);

            }

         ]]>

     </ mx:Script >

     < mx:XMLListCollection  id ="xmlListColl" >

         < mx:source >

             < mx:XMLList >

                 < node  label ="One" >

                     < node  label ="One.1" >

                         < node  label ="One.1.1" >

                             < node  label ="One.1.1.1" >

                                 < node  label ="One.1.1.1.1"   />

                             </ node >

                         </ node >

                     </ node >

                     < node  label ="One.2"   />

                     < node  label ="One.3"   />

                 </ node >

                 < node  label ="Two" >

                     < node  label ="Two.1"   />

                     < node  label ="Two.2"   />

                     < node  label ="Two.3"   />

                 </ node >

                 < node  label ="Three"   />

             </ mx:XMLList >

         </ mx:source >

     </ mx:XMLListCollection >

     < mx:ApplicationControlBar  dock ="true" >

         < mx:CheckBox  id ="checkBox"

                label ="doubleClickEnabled:"

                labelPlacement ="left"

                selected ="true"   />

     </ mx:ApplicationControlBar >

     < mx:Tree  id ="tree"

            dataProvider ="{xmlListColl}"

            labelField ="@label"

            width ="250"

            rowCount ="6"

            doubleClickEnabled ="{checkBox.selected}"

            itemDoubleClick ="tree_itemDoubleClick(event);"

            showScrollTips ="true"   />

</ mx:Application >