JSF rich：tree selectionListener

Question

我是使用rich：tree组件的新手。当我有3个节点时，我的selectionChangeListener方法被正确调用。但是，当选择最里面的节点时，空参数（selectionChangeEvent.getNewSelection()）将被发送到selectionChangeListener方法。

我找不到问题。

<h:panelGrid>
            <rich:tree nodeType="#{node.type}" value="#{kampusBean.mevcutkampus.rootnodes}" var="node" 
                       selectionChangeListener="#{kampusBean.mevcutkampus.selectionChanged}" 
                       toggleType="client" selectionType="ajax" render="paftapanel">
                <rich:treeNode type="Node1">
                    #{node.name}
                </rich:treeNode>
                <rich:treeNode type="Node2">
                    #{node.name}
                </rich:treeNode>
                <rich:treeNode type="Node3">
                    #{node.name}
                </rich:treeNode>
                <rich:treeNode type="Node4">
                    #{node.name}
                </rich:treeNode>
            </rich:tree>
            <a4j:commandButton image="/resources/add.png" action="#{kampusBean.mevcutkampus.addNode1()}"
                               render="paftapanel"/>
</h:panelGrid> 

选择侦听器方法：

public void selectionChanged(TreeSelectionChangeEvent selectionChangeEvent) {

    List<Object> selection = new ArrayList<Object>(selectionChangeEvent.getNewSelection());
    if (selection == null || selection.isEmpty()) {
        return; //when node4 is selected, selection is empty and always returns. 
    }
    Object currentSelectionKey = selection.get(0);
    AbstractTree tree = (AbstractTree) selectionChangeEvent.getSource();

    Object storedKey = tree.getRowKey();
    tree.setRowKey(currentSelectionKey);
    mevcutSecim = (TreeNodeLevel) tree.getRowData();
    tree.setRowKey(storedKey);
}