[AC-3056] Opening/closing the same windows sometimes causes a NullPointerException in Android

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

var win1 = Titanium.UI.createWindow({  
    title:'Window 1'
});

win1.add(openButton = Titanium.UI.createButton({
	title:'Open window 1',
	top: 10
}));

win1.add(openButton2 = Titanium.UI.createButton({
	title:'Open window 2',
	top: 100
}));

openButton.addEventListener('click', function() {
	modal.open();
});

openButton2.addEventListener('click', function() {
	modal2.open();
});

var modal = Titanium.UI.createWindow({
	title:'Modal',
        modal: true
});

modal.add(closeButton = Titanium.UI.createButton({
	title:'Close',
	top: 100
}));

closeButton.addEventListener('click', function() {
	modal.close();
});

var modal2 = Titanium.UI.createWindow({
	title:'Modal 2',
        modal: true
});

modal2.add(closeButton2 = Titanium.UI.createButton({
	title:'Close',
	bottom: 100
}));

closeButton2.addEventListener('click', function() {
	modal2.close();
});

win1.open();