title: Creating a simple vertical layout? Having trouble filling all space
body: <p>I'm having trouble setting up a simple layout. I want a canvas below a vertical panel. Something like:</p>
  
  <pre><code>VerticalPanel parent = new VerticalPanel();
  parent.setWidth("100%");
  parent.setHeight("100%");
  
  HorizontalPanel hp = new HorizontalPanel();
  hp.setWidth("100%");
  parent.add(hp);
  
  Canvas canvas = Canvas.createIfSupported();
  canvas.setWidth("100%");
  canvas.setHeight("100%");
  parent.add(canvas);
  </code></pre>
  
  <p>So basically I want the top panel "hp" to be only as high as its content needs it to be, and the rest of the page should be filled with the canvas element. But I'm getting strange effects, the canvas seems to only fill a portion of the screen etc. It reports its height after layout at around 200px, whereas the available height should be around 600px.</p>
  
  <p>Thanks</p>