public class TestVM {
	private boolean updating;
	private boolean editorEnabled;
	private String text;

	@Command
	@NotifyChange("editorEnabled")
	public void doBeforeClose(
			@ContextParam(ContextType.TRIGGER_EVENT) Event event) {
		event.stopPropagation();
		editorEnabled = false;
		text = null;
	}

	@Command
	@NotifyChange({ "editorEnabled", "text", "updating" })
	public void doEdit() {
		editorEnabled = true;
		text = "automatic text";
		updating = new Random().nextBoolean();
	}

	@Command
	@NotifyChange("editorEnabled")
	public void doSave() throws Exception {
		// persist text or throw exception
		editorEnabled = false;
		text = null;
	}

	public String getText() {
		return text;
	}

	@Init
	public void init() {
		editorEnabled = false;
		text = null;
	}

	public boolean isEditorEnabled() {
		return editorEnabled;
	}

	@DependsOn("text")
	public boolean isSaveDisabled() {
		return text == null || text.trim().isEmpty();
	}

	public boolean isUpdating() {
		return updating;
	}

	public void setText(String text) {
		this.text = text;
	}
}

{code:xml}
<window apply="org.zkoss.bind.BindComposer" viewModel="@id('vm') @init('test.TestVM')">
	<button label="Open Editor" onClick="@command('doEdit')" />
	<window title="@load(vm.updating ? 'Update' : 'Insert')"
		mode="modal" width="30em" height="30ex"
		visible="@load(vm.editorEnabled)" closable="true"
		onClose="@command('doBeforeClose')">
		<vlayout vflex="1">
			<textbox instant="true" rows="2" hflex="1" vflex="1"
				value="@bind(vm.text)" />
		</vlayout>
		<hbox pack="end" width="100%">
			<button label="Save"
				onClick="@command('doSave')" disabled="@load(vm.saveDisabled)" />
		</hbox>
	</window>
</window>