message: Fix white border bug
  contentsRect() for some reason returns a rect that is one pixel off
  from the actual widget's size.  Use the width() and height() instead.
diff: @@ -123,8 +123,7 @@ void ScrollableDisplay::updatePosition()
  break;
  case config::ScrollBarPosition::Hidden: {
  scrollBar_->hide();
  - auto const cr = contentsRect();
  - mainWidget_->resize(cr.right(), cr.bottom());
  + mainWidget_->resize(width(), height());
  mainWidget_->move(0, 0);
  break;
  }
  