Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/11/29/opening-nodes-in-a-flex-tree-control-using-the-expanditem-method/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.events.ListEvent;

            private function comboBox_change(evt:ListEvent):void {
                var team:String = ComboBox(evt.currentTarget).selectedItem.@label;
                var node:XMLList = mlb.league.division.team.(@label == team);
                expandParents(node[0]);

                tree.selectedItem = node[0];
                var idx:int = tree.getItemIndex(node[0]);
                tree.scrollToIndex(idx);
            }

            private function expandParents(node:XML):void {
                if (node && !tree.isItemOpen(node)) {
                    tree.expandItem(node, true);
                    expandParents(node.parent());
                }
            }
        ]]>
    </mx:Script>

    <mx:XML id="mlb" source="mlb.xml" />

    <mx:ApplicationControlBar dock="true">
        <mx:ComboBox id="comboBox"
                prompt="Please select a team..."
                dataProvider="{mlb.league.division.team}"
                labelField="@label"
                change="comboBox_change(event);" />
    </mx:ApplicationControlBar>

    <mx:Tree id="tree"
            dataProvider="{mlb}"
            labelField="@label"
            showRoot="false"
            width="300"
            rowCount="8" />

</mx:Application>

View source is enabled in the following example.

 

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/11/08/scrolling-to-a-specific-index-in-a-flex-list-control/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white"
        creationComplete="init();">
 
    <mx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
 
            private var arrColl:ArrayCollection;
 
            private function init():void {
                var arr:Array = [];
                var n:uint = 50;
                var i:uint;
                for (i = 0; i < n; i++) {
                    arr.push({label:"item " + i, data:i});
                }
                arrColl = new ArrayCollection(arr);
                list.dataProvider = arrColl;
                numericStepper.maximum = arrColl.length - 1;
            }
        ]]>
    </mx:Script>
 
    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="scrollToIndex(n):">
                <mx:NumericStepper id="numericStepper"
                        change="list.scrollToIndex(event.value);" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>
 
    <mx:List id="list"
            rowCount="5"
            width="100" />
 
</mx:Application>

View source is enabled in the following example.