window.go
func (w *Window) resize(x, y int) {
	w.x = x
	w.y = y
	w.backingStore = make([]Cell, x*y)

	// iterate over widgets
	for _, widget := range w.widgets {
		widget.Resize()
	}
}
func (w *Window) resize(x, y int) {
	w.x = x
	w.y = y
	w.backingStore = make([]Cell, x*y)

	// iterate over widgets
	for _, widget := range w.widgets {
		widget.Resize()
	}
}
// resize sets new x and y maxima.
// resize shall be called from queue context.