title: Disabled splitter in qt designer
body: <p>I'm using qt 4.8.0 on windows 7.
  When I open qt designer and create widget in it, I cannot set 'Lay Out in a vertical/horizontal in Splitter'. Also there is no Splitter in a Layouts widget box.
  All other layouts are working well.</p>
  
  <p>Have anyone run into same or similar problem?</p>