I am stuck in getting an absolute position of DialogBox. I know it is the common problem (and strange workaround) for  PopupPanel (which is parent to DialogBox) to set it, but what if I want to get it, what is the exact moment when the box attached to DOM? Neither overriding show nor onAttach nor show does not help:
class MyDialog extends DialogBox {
    public MyDialog(. . .) {
        ComplexPanel vert = new VerticalPanel();
        vert.add("Test");
        vert.add(new Button("Close", new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                MyDialog.this.hide();
            }
        }));
        setWidget(vert);
        this.addAttachHandler(new AttachEvent.Handler() {
            @Override
            public void onAttachOrDetach(AttachEvent event) {
                if (event.isAttached()) Log.debug("attach:"+MyDialog.this.getAbsoluteLeft() +";"+
                                                            MyDialog.this.getAbsoluteTop());
            }
        });
    }
    @Override
    protected void onLoad() {
        super.onLoad();
        Log.debug("load:"+this.getAbsoluteLeft() +";"+this.getAbsoluteTop());
    }
    @Override
    public void show() {
        super.show();
        Log.debug("show:"+this.getAbsoluteLeft() +";"+this.getAbsoluteTop());
    }
}
So when I call new MyDialog().show();, all this lines do log 0;0, however dialog is positioned in center of a page. But what I want is the sum of the chain of offsetParent positions. (And they are 0 in these moments even in JavaScript, if use JSNI to check this)
Again, setPopupPositionAndShow allows to set position but not get it :(