title: vaadin floating(dynamic ?) layout
body: <p>I use vaadin 7. I am not sure whether the "floating layout" is the proper term so let me describe what I want. 
  I have more panels inside a layout. The size of those panels are fixed. If the browser window is large enough they are arranged next to each other <em>horizontally</em>. If the window does not have enough space for all of them horizontally, then the panels should be arranged <em>vertically</em>.</p>
  
  <p>1, What is this kind of layout called? Floating? Dynamic?</p>
  
  <p>2, How to achieve this with vaadin 7?</p>
  
  <p>Neither <code>horizontalLayout.setSizeUndefined()</code> nor <code>horizontalLayout.setSizeFull()</code> work.
  I am not even sure whether I need HorizontalLayout or something else.</p>