Simple application layout footer positioning

Hi

I am trying to achieve a very basic application layout.. There should be a Header on top, a body area in the middle and a footer at the bottom of the browser window.

I want the footer to be at the bottom of the browser window all the time.. I thought it was simple but has been struggling..

If if add mainWindow.getContent().setSizeFull(); i get the footer to be at the bottom all the time.. but the browser will not have a scroll bar when the contents are more..
If i remove the setSizeFull() line, i get the scroll bar, but the footer will come up when the content on the page is less..

What am i missing here...

Here is the code for that..

// Create the main window.
Window mainWindow = new Window("Test");

// Add the header component.
VerticalLayout headerPanel = new VerticalLayout();
headerPanel.setHeight("110px");
mainWindow.getContent().addComponent(headerPanel);
((VerticalLayout)mainWindow.getContent()).setComponentAlignment(headerPanel, Alignment.TOP_CENTER);

// Add a horizontal layout for the body part.
HorizontalLayout body = new HorizontalLayout();
body.setWidth("990px");
mainWindow.getContent().addComponent(body);
((VerticalLayout)mainWindow.getContent()).setComponentAlignment(body, Alignment.TOP_CENTER);

//add the footer
footer.addStyleName("footer");
footer.setHeight("75px");
mainWindow.getContent().addComponent(footer);
((VerticalLayout)mainWindow.getContent()).setComponentAlignment(footer, Alignment.BOTTOM_CENTER);

setMainWindow(mainWindow);

Thanks in advance

Hari

I think easiest would be to wrap the middle part to a Panel.