I create object of a Window class, call open() method and get pretty additional window for my AIR-application. If i call close() method, then window dispatchs CLOSING event, closes window and dispatchs a CLOSE event. Then i can call open() method again and window opens one more time.
But if user closes window by system chrome or using alt+F4, then no events will be dispatched. And although the window is closed, i can't open it with open() method.