Transition error

appjs

Titanium.UI.setBackgroundColor('#000');

var win1 = Ti.UI.createWindow({
    backgroundColor: 'white'
});
var btn1 = Ti.UI.createButton({
    title: 'Goto 2 - without animation (no error)',
	width:300,
	height:100,
	top:100
});
var btn2 = Ti.UI.createButton({
    title: 'Goto 2 - with animation (with error)',
	width:300,
	height:100,
	top:220
});

btn1.addEventListener('click', function(e){
	var win2 = Ti.UI.createWindow({
   		backgroundColor: 'blue'
	});
	win2.open();
	
	var btn3 = Ti.UI.createButton({
    	title: 'Go back',
		width:300,
		height:100
	});

	btn3.addEventListener('click', function(e){
		win2.close();
	});

	win2.add(btn3);
});

btn2.addEventListener('click', function(e){
	var win2 = Ti.UI.createWindow({
   		backgroundColor: 'blue'
	});
	win2.open({transition:Ti.UI.iPhone.AnimationStyle.FLIP_FROM_RIGHT});
	
	var btn3 = Ti.UI.createButton({
    	title: 'Go back',
		width:300,
		height:100
	});

	btn3.addEventListener('click', function(e){
		win2.close();
	});
	
	win2.add(btn3);
});

win1.add(btn1);
win1.add(btn2);
win1.open();