public PropertyPanel addProp(String key, String label, String value) {
        properties.add(new Prop(key, label, value));
        return this;
    }
@Test
    public void objectValue() {
        basic();
        pp.addProp(KEY_A, KEY_A, new FooClass("a"))
                .addProp(KEY_B, KEY_B, new FooClass("bxyyzy"), "[xz]");

        validateProp(KEY_A, ">a<");
        validateProp(KEY_B, ">byyy<");
    }