code: func (b *BoxLayout) Resize() {
  	b.layout()
  
  	// Now also let the children know we resized.
  	for i := range b.cells {
  		b.cells[i].widget.Resize()
  	}
  	b.PostEventWidgetResize(b)
  }
docs: // Resize adjusts the layout when the underlying View changes size.