title: Qt Designer make widget overlap another widget in layout
body: <p>I want to make 3 window button like above picture (similar Google Chrome) use Qt Designer and PyQt.</p>
  
  <p>I want 3 buttons overlap right side of TabWidget. 
  But I only can overlap the Button on TabWidget when break layout like the picture.</p>
  
  <p>When I set any layout, every widget can not overlap on each other. 
  So can I overlap when set layout? Thanks. </p>
  
  <p>This is the layout I want</p>
  
  <p><img src="https://i.stack.imgur.com/mTkRU.jpg" alt=""></p>
  
  <p>It similar Google Chrome's layout </p>
  
  <p><img src="https://i.stack.imgur.com/yIorD.jpg" alt=""></p>