ttk.go
func NewWindow(manager Windower) *Window {
	wc := make(chan *Window)
	Queue(func() {
		w := &Window{
			id:           lastWindowID,
			mgr:          manager,
			x:            maxX,
			y:            maxY,
			focus:        -1, // no widget focused
			backingStore: make([]Cell, maxX*maxY),
			widgets:      make([]Widgeter, 0, 16),
		}
		lastWindowID++
		windows[w.id] = w
		windower2window[manager] = w
		manager.Init(w)
		wc <- w
	})
	return <-wc
}
func NewWindow(manager Windower) *Window {
	wc := make(chan *Window)
	Queue(func() {
		w := &Window{
			id:           lastWindowID,
			mgr:          manager,
			x:            maxX,
			y:            maxY,
			focus:        -1, // no widget focused
			backingStore: make([]Cell, maxX*maxY),
			widgets:      make([]Widgeter, 0, 16),
		}
		lastWindowID++
		windows[w.id] = w
		windower2window[manager] = w
		manager.Init(w)
		wc <- w
	})
	return <-wc
}
// NewWindow creates a new window type.