решаемая.
<mx:Script>
<![CDATA[
import mx.collections.ICollectionView;
import mx.events.ListEvent;
private function tree_itemClick(evt:ListEvent):void {
var item:Object = Tree(evt.currentTarget).selectedItem;
if (tree.dataDescriptor.isBranch(item)) {
tree.expandItem(item, !tree.isItemOpen(item), true);
}
}
]]>
<mx:XML id="dp">
<root>
<folder label="One">
<folder label="One.A">
<item label="One.A.1" />
<item label="One.A.2" />
<item label="One.A.3" />
<item label="One.A.4" />
<item label="One.A.5" />
</folder>
<item label="One.1" />
<item label="One.2" />
</folder>
</root>
</mx:XML>
<mx:Tree id="tree" dataProvider="{dp}" showRoot="false" labelField="@label" width="300" rowCount="6"
itemClick="tree_itemClick(event);" />