ChildWindow.zul

<?init class="org.zkoss.zkplus.databind.AnnotateDataBinderInit" arg0="childwindow" ?>
<?page title="Child Window" contentType="text/html;charset=UTF-8"?>
<zk>
  <window id="childwindow" title="Child Window" border="normal"
		mode="modal" width="30%" apply="org.com.demo.ChildWindowController">
		<label value="Change the first name and Last name and click the button close to return the values"></label>
		<separator></separator>
		<label value="First Name"></label>
		<separator></separator>
		<textbox id="firstName" value="@{childwindow$ChildWindowController.firstName}"></textbox>
		<separator></separator>
		<label value="Last Name"></label>
		<separator></separator>
		<textbox id="lastName"
			value="@{childwindow$ChildWindowController.lastName}">
		</textbox>
		<separator></separator>
		<separator></separator>
		<button id="btn" label="Close"></button>
	</window>
</zk>

ChildWindowController

package org.com.demo;

import java.util.HashMap;

import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.Execution;
import org.zkoss.zk.ui.Executions;
import org.zkoss.zk.ui.event.Event;
import org.zkoss.zk.ui.event.EventQueue;
import org.zkoss.zk.ui.event.EventQueues;
import org.zkoss.zk.ui.event.Events;
import org.zkoss.zk.ui.select.SelectorComposer;
import org.zkoss.zk.ui.select.annotation.Listen;
import org.zkoss.zk.ui.select.annotation.Wire;
import org.zkoss.zul.Button;
import org.zkoss.zul.Messagebox;
import org.zkoss.zul.Textbox;
import org.zkoss.zul.Window;

@SuppressWarnings("serial")
public class ChildWindowController extends SelectorComposer<Component> {

  @Wire
	Button btn;
	
	@Wire
	Window childwindow;
	
	private Window parentWindow;
	
	private String firstName;
	private String lastName;

	public String getFirstName() {
		return firstName;
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}

	public String getLastName() {
		return lastName;
	}

	public void setLastName(String lastName) {
		this.lastName = lastName;
	}

	public void doAfterCompose(Component comp) throws Exception {
		super.doAfterCompose(comp);
		 
		final Execution execution = Executions.getCurrent();
		setFirstName((String) execution.getArg().get("firstName"));
		setLastName((String) execution.getArg().get("lastName"));
		parentWindow = (Window) execution.getArg().get("parentWindow");
		 

	}

	@Listen("onClick = button#btn")
	public void changeLabel() {
		
		final HashMap<String, Object> map = new HashMap<String, Object>();
		map.put("firstName", this.firstName);
		map.put("lastName", this.lastName);
		
		childwindow.detach();
		Events.sendEvent(new Event("onSaved", parentWindow));
	}

}

ParentWindow.zul

<?page title="Parent Window" contentType="text/html;charset=UTF-8"?>
<zk>
  <window id="parentWindow" title="Parent Window" border="normal" apply="org.com.demo.ParentWindowController">
		<label value="First Name"></label>
		<separator></separator>
		<textbox id="firstName"></textbox>
		<separator></separator>
		<label value="Last Name"></label>
		<separator></separator>
		<textbox id="lastName"></textbox>
		<separator></separator>
		<button label="Show Window" id="showWindow"></button>
	</window>
</zk>

ParentWindowController

package org.com.demo;

import java.util.HashMap;

import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.Executions;
import org.zkoss.zk.ui.SuspendNotAllowedException;
import org.zkoss.zk.ui.event.Event;
import org.zkoss.zk.ui.event.EventListener;
import org.zkoss.zk.ui.event.EventQueue;
import org.zkoss.zk.ui.event.EventQueues;
import org.zkoss.zk.ui.select.SelectorComposer;
import org.zkoss.zk.ui.select.annotation.Listen;
import org.zkoss.zk.ui.select.annotation.Wire;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zul.Messagebox;
import org.zkoss.zul.Textbox;
import org.zkoss.zul.Window;

@SuppressWarnings("serial")
public class ParentWindowController extends   SelectorComposer<Window> {

  @Wire
	private Window parentWindow;
	@Wire
	Textbox firstName;
	@Wire
	Textbox lastName;

	@SuppressWarnings({ "rawtypes", "unchecked" })
	public void doAfterCompose(Window comp) throws Exception {
		super.doAfterCompose(comp); // wire variables and event listners

	}

	@Listen("onClick=#showWindow")
	public void showChild() {
		final HashMap<String, Object> map = new HashMap<String, Object>();
		map.put("firstName", firstName.getValue());
		map.put("lastName", lastName.getValue());
		map.put("parentWindow", parentWindow);
		Executions.createComponents(
				"ChildWindow.zul", null, map);

	}

	/**
	 * This method is actualy an event handler triggered only from the Child
	 * window dialog and it is responsible to reflect the data changes
	 * 
	 */
	public void onSaved(Event event) {
		Messagebox.show("OnSaved");
	}

}