Don't allow resource previews to have negative sizes
Don't allow resource previews to have negative sizes

* This isn't a real bug, it only happens temporarily during first show of a
  window while the geometry is all messed up, but it causes some error spam in
  the log so it's better to fix.
TurtleRockStudios/renderdoc_public,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,Zorro666/renderdoc,baldurk/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,Zorro666/renderdoc