Inconsistent setFocus and tab sequence behaviors

protected Textbox movieNameTxtBox; // autowired
. . .

public void  onCreate$winModal(Event event ) {
   . . . 
   movieNameTxtBox.setFocus(true);
}

<?xml version="1.0" encoding="UTF-8" ?>

<zk xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
	xmlns='http://www.zkoss.org/2005/zul'
	xmlns:h='http://www.w3.org/1999/xhtml'
	xsi:schemaLocation='http://www.zkoss.org/2005/zul WEB-INF/xsd/zul.xsd'>


	<window id='testWin' apply='de.forsthaus.example.ControllerTestWin'
		border='normal' title='A Test Page'>

		<!-- This listbox display the movies names  -->
		<listbox id='detailLstBox' width='200px' checkmark='true'>
			<listhead sizable='true'>
				<listheader label='Name' />
			</listhead>
			<listitem label='Tom And Jerry' value='Tom And Jerry' />
			<listitem label='Tweety and Sylvester'
				value='Tweety and Sylvester' />
			<listitem label='Bugs Bunny' value='Bugs Bunny' />
		</listbox>

		<space spacing='1px' />

		<!-- Edit button to edit the selected row -->
		<button id='editBtn' label='Edit Record' autodisable='self' />

	</window>
</zk>

package de.forsthaus.example;

import java.util.HashMap;

import org.zkoss.zk.ui.Executions;
import org.zkoss.zk.ui.event.Event;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zul.Button;
import org.zkoss.zul.Listbox;
import org.zkoss.zul.Messagebox;
import org.zkoss.zul.Window;

/** Controller class for test_tab_sequence.zul page */

public class ControllerTestWin extends GenericForwardComposer {

	private static final long serialVersionUID = 1L;

	/**
	 * ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	 * 1. All the components that are defined here and have a corresponding
	 * component with the same 'id' in the zul-file are getting autowired by the
	 * GenericForwardComposer. Means you can acces them directly by their ID. <br>
	 * 2. You can call their events bei naming conventions. i.e.<br>
	 * EventName|Seperator|ComponentId <br>
	 * onClick$saveBtn(Event event){your code here}
	 * ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	 */
	protected Window testWin; // autowired
	protected Listbox detailLstBox; // autowired
	protected Button editBtn; // autowired

	/** Constructor */
	public ControllerTestWin() {
	}// end constructor

	// ======================Event Handlers===================

	/**
	 * when you click the Edit Record button
	 * 
	 * @throws InterruptedException
	 */
	public void onClick$editBtn(Event event) throws InterruptedException {

		if (detailLstBox.getSelectedItem() != null) {

			String str = (String) detailLstBox.getSelectedItem().getValue();

			// Map that holds params that we need in the new created Window
			HashMap<String, Object> paramMap = new HashMap<String, Object>();
			paramMap.put("mySelectedItem", str);

			// create the Window and overhanded a map with params
			Executions.createComponents("/test/test_tab_sequenceModal.zul", testWin, paramMap);
		} else {
			Messagebox.show("Please select a row first.");
		}
	}// end method

	/** when you click the Save Record button on the Edit Sub-Window */
	public void onClick$saveEditBtn(Event event) throws InterruptedException {
		// Some action
	}// end method

}// end class

<?xml version="1.0" encoding="UTF-8"?>

<zk xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
	xmlns='http://www.zkoss.org/2005/zul'
	xmlns:h='http://www.w3.org/1999/xhtml'
	xsi:schemaLocation='http://www.zkoss.org/2005/zul WEB-INF/xsd/zul.xsd'>

	<!-- ========= Pop-up window to edit selected record ============ -->
	<window id='subEditWin'
		apply='de.forsthaus.example.ControllerTestWinModal' width='500px'
		border='normal' title='Edit Sub-Window'>

		<label value='Movie name:' />
		<textbox id='movieNameTxtBox' width='80%' constraint='no empty' />

		<separator />
		<h:center>
			<button id='saveEditBtn' label='Save Record'
				autodisable='self' />

			<button id='closeSubWinBtn' label='Close Window' />
		</h:center>
	</window>
	<!-- ========= End of pop-up Window ============ -->

</

package de.forsthaus.example;

import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.SuspendNotAllowedException;
import org.zkoss.zk.ui.event.Event;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zul.Button;
import org.zkoss.zul.Textbox;
import org.zkoss.zul.Window;

/** Controller class for test_tab_sequenceModal.zul page */

public class ControllerTestWinModal extends GenericForwardComposer {

	private static final long serialVersionUID = 1L;

	/**
	 * ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	 * 1. All the components that are defined here and have a corresponding
	 * component with the same 'id' in the zul-file are getting autowired by the
	 * GenericForwardComposer. Means you can acces them directly by their ID. <br>
	 * 2. You can call their events bei naming conventions. i.e.<br>
	 * EventName|Seperator|ComponentId <br>
	 * onClick$saveBtn(Event event){your code here}
	 * ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	 */
	protected Window subEditWin; // autowired
	protected Textbox movieNameTxtBox; // autowired
	protected Button saveEditBtn; // autowired
	protected Button closeSubWinBtn; // autowired

	private String movieTitle;

	/** Constructor */
	public ControllerTestWinModal() {
	}// end constructor

	@Override
	public void doAfterCompose(Component window) throws Exception {
		super.doAfterCompose(window);

		// Read back the overhanded param from the map.
		if (this.arg.containsKey("mySelectedItem")) {
			setMovieTitle((String) this.arg.get("mySelectedItem"));
		} else {
			setMovieTitle(null);
		}
	}

	// ======================Event Handlers ====================

	public void onCreate$subEditWin(Event event) throws SuspendNotAllowedException, InterruptedException {

		movieNameTxtBox.setValue(getMovieTitle()); // set the value
		movieNameTxtBox.setFocus(true); // set the focus

		subEditWin.doModal(); // show window in modal-mode
	}

	/** when you click the Save Record button on the Edit Sub-Window */
	public void onClick$saveEditBtn(Event event) throws InterruptedException {
		// Some action
	}// end method

	/** when you click the Close Window button on the Edit Sub-Window */
	public void onClick$closeSubWinBtn(Event event) throws InterruptedException {
		subEditWin.onClose();
	}// end method

	// ===================== Setter / Getter ====================

	public void setMovieTitle(String movieTitle) {
		this.movieTitle = movieTitle;
	}

	public String getMovieTitle() {
		return movieTitle;
	}

}// end class