<zk>	
	<window id="win" apply="test.TestComposer">
		open chosenbox and press 'ESC' key ... you can see bug (window closes but open chosenbox remains visible) 
		<div></div>
		<chosenbox id="cbx" width="500px" model="${win$composer.getModel()}" emptyMessage="------------------"/>
	</window>
</zk>

package test;
import java.util.*;
import org.zkoss.zk.ui.event.*;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zkmax.zul.Chosenbox;
import org.zkoss.zul.*;

public class TestComposer extends GenericForwardComposer {
		private transient Window win;
		private transient Chosenbox cbx;
		
		List<String> lst = Arrays.asList(new String[]{"first", "second", "third"});
		
		/*
		 * Binding definition
		 */
		
		public ListModelList<String> getModel(){
			return new ListModelList<String>(lst);
		}

		public void onCancel$win(ForwardEvent event) {
			Events.postEvent(new Event(Events.ON_CLOSE, win, null));
		}	
	}