First set a flag to get the indication to apply fade in or fade out effect on the window component.
And, for the fade in fade out effect user 'Tween' and '_alpha'.
Like, for fade in use
var alphaTween = new Tween(movieClip, "_alpha", Regular.easeIn, 0, 100, 40, false);
Same way use for fade out by setting values swapping values 100 and 0.
That's great! Thank you very much.