title: Expandable list view with customized scrollbar in Qt
body: <p>I want to build a widget like this one that we can find in Word :</p>
  
  <p><a href="https://i.stack.imgur.com/kir7V.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kir7V.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/8Ky4E.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8Ky4E.jpg" alt="enter image description here"></a></p>
  
  <p>So, there is a list view using a specific scrollbar with 3 buttons and no scroll.</p>
  
  <p>When you click on the last button at the bottom right, a new list view with a classic scrollbar is shown over the previous list view (hidden when losing focus). So basically, the smae behavior as the one in Word.</p>
  
  <p>We are already capable of displaying a list view with custom content.
  My main concern is how to build the widget in the first image: the list view with the custom scrollbar (3 buttons, no scroll)?</p>
  
  <p>What is the proper way to do this ?</p>