Java - 为什么此焦点遍历策略不会遍历文本区域/组合框？

Question

我还在学习自定义遍历政策，这确实让我误解了几个小时。为什么它不会遍历文本区域？它只跳过文本字段。

所以这些是我添加的一些组件。

    Vector<Component> order = new Vector<Component>(11);
    order.add(txtfldBRN);
    order.add(txtfldName);
    order.add(cmbxDOBirth);
    order.add(txtfldBirthPlace);
    order.add(txtfldMother);
    order.add(txtfldFather);
    order.add(cmbxDOBaptism);
    order.add(txtfldMinister);
    order.add(txtAreaSponsors);
    order.add(txtAreaComments);
    order.add(btnSave);

    static MyOwnFocusTraversalPolicy newPolicy = new MyOwnFocusTraversalPolicy(order);
    this.setFocusTraversalPolicy(newPolicy);
}

public static class MyOwnFocusTraversalPolicy extends FocusTraversalPolicy {
    Vector<Component> order;

    public MyOwnFocusTraversalPolicy(Vector<Component> order) {
        System.out.println(order.size());
        this.order = new Vector<Component>(order.size());
        this.order.addAll(order);
    }

    public Component getComponentAfter(Container focusCycleRoot,
            Component aComponent) {
        int idx = (order.indexOf(aComponent) + 1) % order.size();
        return order.get(idx);
    }

    public Component getComponentBefore(Container focusCycleRoot,
            Component aComponent) {
        int idx = order.indexOf(aComponent) - 1;
        if (idx < 0) {
            idx = order.size() - 1;
        }
        System.out.println("Before: "+idx);
        return order.get(idx);
    }

    public Component getDefaultComponent(Container focusCycleRoot) {
        return order.get(0);
    }

    public Component getLastComponent(Container focusCycleRoot) {
        return order.lastElement();
    }

    public Component getFirstComponent(Container focusCycleRoot) {
        return order.get(0);
    }
}