title: GTK: ScrolledWindow wants infinite space, how to limit it?
body: <p>I create a large TreeView within a GTK ScrolledWindow within a hpaned within a notebook within the toplevel window (and toplevel window has a limited default size).</p>
  
  <p>When I create a ScrolledWindow with TreeView within, it gets allocated as much space as TreeView takes (which is greater than the screen size) and my toplevel window is resized to infinity. How do I limit ScrolledWindow's allocation or its Viewport size? What's the mechanism that determines its default size?</p>