Absolute positions in a ScrollPanel differ between IE and FF about gwt HOT 9 CLOSED

Here is some testing code that shows the problem:
public void onModuleLoad() {
    final RootPanel root = RootPanel.get();
    FlexTable t = new FlexTable();
    root.add(t);
    ScrollPanel p = new ScrollPanel();
    p.setWidth("300px");
    p.setHeight("300px");
    root.add(p);
    p.add(t);
    t.setWidth("600px");
    t.setHeight("600px");
    t.setBorderWidth(10);
    t.setWidget(0,0,createLocationButton(p, "top left"));
    t.setWidget(0,1,createLocationButton(p, "top right"));
    t.setWidget(1,0,createLocationButton(p, "bottom left"));
    t.setWidget(1,1,createLocationButton(p, "bottom right"));
  }

  private Button createLocationButton(ScrollPanel p, String title) {
    final Button b = new Button(title);
    b.addClickListener(new ClickListener(){
      public void onClick(Widget sender) {
        Window.alert("Left:" + b.getAbsoluteLeft() + "\nTop:" +b.getAbsoluteTop() );
      }
    });
    return b;
  }
}

Below is a more complete test. Fails for Opera.

  public void onModuleLoad() {
    final RootPanel root = RootPanel.get();
    root.add(new Label("check scroll offset"));
    FlexTable t = new FlexTable();
    root.add(t);
    ScrollPanel p = new ScrollPanel();
    p.setWidth("300px");
    p.setHeight("300px");
    root.add(p);
    p.add(t);
    t.setWidth("600px");
    t.setHeight("600px");
    t.setBorderWidth(10);
    t.setWidget(0,0,createLocationButton(p, "top left"));
    t.setWidget(0,1,createLocationButton(p, "top right"));
    t.setWidget(1,0,createLocationButton(p, "bottom left"));
    t.setWidget(1,1,createLocationButton(p, "bottom right"));
    root.add(new Label("Check border offset"));
    final FlowPanel flowPanel = new FlowPanel();
    root.add(flowPanel);
    flowPanel.setStyleName("my-BigBorder");
    flowPanel.setSize("409px", "195px");

    {
      final Button button = new Button();
      flowPanel.add(button);
      button.addClickListener(new ClickListener() {
        public void onClick(Widget e) {
           Window.alert("flowPanel location: " + flowPanel.getAbsoluteLeft() + ", "
            + flowPanel.getAbsoluteTop() + "\nbutton location: " +
button.getAbsoluteLeft() + ", "
            + button.getAbsoluteTop());
        }
      });
      button.setText("getLocation");
    }
  }


  private Button createLocationButton(ScrollPanel p, String title) {
    final Button b = new Button(title);
    b.addClickListener(new ClickListener(){
      public void onClick(Widget sender) {
        Window.alert("Left:" + b.getAbsoluteLeft() + "\nTop:" +b.getAbsoluteTop() );
      }
    });
    return b;
  }

#added absolutely possitions button to example above
  public void onModuleLoad() {
    final RootPanel root = RootPanel.get();
    root.add(new Label("______Scroll offset"));
    FlexTable t = new FlexTable();
    root.add(t);
    ScrollPanel p = new ScrollPanel();
    p.setWidth("300px");
    p.setHeight("300px");
    root.add(p);
    p.add(t);
    t.setWidth("600px");
    t.setHeight("600px");
    t.setBorderWidth(10);
    t.setWidget(0,0,createLocationButton("top left"));
    t.setWidget(0,1,createLocationButton("top right"));
    t.setWidget(1,0,createLocationButton("bottom left"));
    t.setWidget(1,1,createLocationButton("bottom right"));
    root.add(new Label("Check border offset"));
    final FlowPanel flowPanel = new FlowPanel();
    root.add(flowPanel);
    flowPanel.setStyleName("my-BigBorder");
    flowPanel.setSize("409px", "195px");

    {
      final Button button = new Button();
      flowPanel.add(button);
      button.addClickListener(new ClickListener() {
        public void onClick(Widget e) {
           Window.alert("flowPanel location: " + flowPanel.getAbsoluteLeft() + ", "
            + flowPanel.getAbsoluteTop() + "\nbutton location: " +
button.getAbsoluteLeft() + ", "
            + button.getAbsoluteTop());
        }
      });
      button.setText("getLocation");
    }

    Button absolute= createLocationButton("absolute");
    root.add(absolute, 10,10);
  }


  private Button createLocationButton(String title) {
    final Button b = new Button(title);
    b.addClickListener(new ClickListener(){
      public void onClick(Widget sender) {
        Window.alert("Left:" + b.getAbsoluteLeft() + "\nTop:" +b.getAbsoluteTop() );
      }
    });
    return b;
  }

Fixed on Mozilla by manually crawling through parents and looking for scroll panels.

Related discussion:
http://groups.google.com/group/Google-Web-Toolkit/browse_thread/thread/c908d345afb514f1/