[TIMOB-9151] iOS: Blank screen when pressing back in navigationGroup

// this sets the background color of the master UIView (when there are no windows/tab groups on it)
var rootwin = Ti.UI.createWindow({
	navBarHidden:true,
	top:'0dp',
	bottom:'0dp',
	left:'0dp',
	right:'0dp',
	orientationModes:[Titanium.UI.LANDSCAPE_LEFT, Titanium.UI.LANDSCAPE_RIGHT]
});

var rootNav = Ti.UI.iPhone.createNavigationGroup({
	window:rootwin,
	orientationModes:[Titanium.UI.LANDSCAPE_LEFT, Titanium.UI.LANDSCAPE_RIGHT]
});

var win1 = Ti.UI.createWindow({
	backgroundColor:'red',
	navBarHidden:true,
	top:0,
	left:0,
	right:0,
	bottom:0
});

var nextPage = Ti.UI.createButton({
	title:'Next Page',
	width:'300dp',
	height:'50dp',
	top:0,
	left:0
});
win1.add(nextPage);

var testView = Ti.UI.createView({
	backgroundColor:'gray',
	//width:Ti.UI.FILL,
	height:'300dp',
	top:'50dp',
	bottom:0,
	right:0,
	left:0
});
win1.add(testView);

nextPage.addEventListener('click', function(){
	
	var newWin = Ti.UI.createWindow({
		backgroundColor:'blue',
		navBarHidden:true,
		top:0,
		left:0,
		right:0,
		bottom:0
	});
	
	var backButton = Ti.UI.createButton({
		title:'Back',
		width:'300dp',
		height:'50dp',
		top:0,
		left:0
	});
	backButton.addEventListener('click', function(){
		nav1.close(newWin);
	});
	newWin.add(backButton);
	
	nav1.open(newWin);
});

var nav1 = Ti.UI.iPhone.createNavigationGroup({
	window:win1,
	top:0,
	left:0,
	right:0,
	bottom:0,
	visible:false
});

var wrapperwin = Ti.UI.createWindow({
	navBarHidden:true,
	top:0,
	left:0,
	right:0,
	bottom:0
});
wrapperwin.add(nav1);

rootwin.add(wrapperwin);

rootwin.open();
nav1.visible = true;