how to add uibinder widget to gxt dialog? Layouts not working and contents disappear on resize

[Ilya Basin]

Someone please tell me, how to correctly use uibinders and what's wrong with this code:

package foo.client;

import com.extjs.gxt.ui.client.widget.Dialog;
import com.extjs.gxt.ui.client.widget.layout.FitLayout;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.RootPanel;

public class HW implements EntryPoint {
    public void onModuleLoad() {
    	Dialog w = new Dialog();
    	w.setHeading("abc");
        w.setSize(1000,600);
        w.setResizable(true);
        w.setButtons("");
        w.setLayout(new FitLayout());
        w.add(new TestUIBinder());
        w.setPosition(10, 50);
        RootPanel.get().add(w);
    }
}

package foo.client;

import com.extjs.gxt.ui.client.widget.form.FieldSet;
import com.google.gwt.core.client.GWT;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.Widget;

public class TestUIBinder extends Composite {

	private static TestUIBinderUiBinder uiBinder = GWT
			.create(TestUIBinderUiBinder.class);

	interface TestUIBinderUiBinder extends
			UiBinder<Widget, TestUIBinder> {
	}

	public TestUIBinder() {
		initWidget(uiBinder.createAndBindUi(this));
	}

	@UiField
	FieldSet fieldSet;
}

TestUIBinder.ui.xml:
<!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent"> <ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder" xmlns:g="urn:import:com.google.gwt.user.client.ui" xmlns:gxt="urn:import:com.extjs.gxt.ui.client.widget" xmlns:gxt-form="urn:import:com.extjs.gxt.ui.client.widget.form" > <gxt-form:FieldSet ui:field="fieldSet" heading="x"> </gxt-form:FieldSet> </ui:UiBinder>