// given:
        DesktopAgent desktop =  navigate("/focus.zul");

        // when:
        ComponentAgent comboAgent = desktop.query("combobox[id='combo']");
        Combobox combobox = comboAgent.as(Combobox.class);
        comboAgent.click();

        ComponentAgent textAgent = desktop.query("textbox[id='text']");
        Textbox textbox = comboAgent.as(Textbox.class);
        textAgent.click();

<idspace apply="org.zkoss.bind.BindComposer"
             viewModel="@id('vm') @init('net.nfon.portal.component.FocusComponentsVM')"
             binder="@init(queueScope='group')">
        <combobox id="combo" onFocus="@command('focus')" onBlur="@command('blur')"/>
        <textbox id="text"  onFocus="@command('focus')" onBlur="@command('blur')"/>
    </idspace>

 @Command
    public void focus(@ContextParam(ContextType.TRIGGER_EVENT) Event event) {
        System.out.println("focus");
    }

    @Command
    public void blur(@ContextParam(ContextType.TRIGGER_EVENT) Event event) {
        System.out.println("blur");
    }