rich:changeExpandListener does not apply to children

[vata2999]

Hi,

I created a rich tree with changeExpandListener. it runs only at root level of my tree and does not apply to children that are being added by the listener dynamically .

what should I do ?

here is my code

<rich:tree id="programTree"
                ajaxKeys="#{_item.id}"
                 switchType="ajax"
                value="#{programTreeList.treeNode}" var="_item">
                <rich:changeExpandListener type="com.test.ui.TreeNodeXpander"/>              
                <rich:treeNode >
                    <h:outputText value="#{_item.programName}" />
               </rich:treeNode>
</rich:tree>

public class TreeNodeXpander implements NodeExpandedListener
{

  
    @Override
    public void processExpansion(NodeExpandedEvent nodeExpandedEvent) throws AbortProcessingException
    {      
        Object source = nodeExpandedEvent.getSource();
        if (source instanceof HtmlTree)
        {
            HtmlTree tree = (HtmlTree) source;          
            Object rowKey = tree.getRowKey();
            TreeNode modelTreeNode = tree.getModelTreeNode(rowKey);
            Program rowData = (Program) tree.getRowData(rowKey);
            List<Program> list = fetchChildren(rowData, modelTreeNode);
            if (CollectionUtil.isNotEmpty(list))
            {
                for (Program program : list)
                {
                    TreeNodeImpl<Program> tp = new TreeNodeImpl<Program>();
                    tp.setData(program);
                    modelTreeNode.addChild(program.getId(), tp);//won't expand 
                }
            }

        }

    }

PS : I am trying to create a partial(lazy) loading tree.