[TIMOB-15716] iOS: tabGroup window flickers on open if barImage or rightNavButton is set

var tabGroup = Titanium.UI.createTabGroup();

var win1 = Titanium.UI.createWindow({  
    title:'Tab 1',
    backgroundColor:'#fff'
});
var tab1 = Titanium.UI.createTab({  
    icon:'KS_nav_views.png',
    title:'Tab 1',
    window:win1
});
var btn=Ti.UI.createButton({
	title:'Details'
});
var newWin=Ti.UI.createWindow({
	title:'I am Window 1',
	backgroundColor:'red',
	barImage:'KS_nav_ui.png',
	rightNavButton:btn
});

var label1 = Titanium.UI.createLabel({
	color:'#999',
	text:'I am Window 1',
	font:{fontSize:20,fontFamily:'Helvetica Neue'},
	textAlign:'center',
	width:'auto'
});

win1.add(label1);
label1.addEventListener('click',function(){
	tab1.open(newWin);
});

var win2 = Titanium.UI.createWindow({  
    title:'Tab 2',
    backgroundColor:'#fff'
});
var tab2 = Titanium.UI.createTab({  
    icon:'KS_nav_ui.png',
    title:'Tab 2',
    window:win2
});


tabGroup.addTab(tab1);  
tabGroup.addTab(tab2);  


tabGroup.open();