[TIMOB-19166] iOS: Left nav button is invisible (on the second tab) when the right nav button is replaced

(function() {
	var tabGroup = Titanium.UI.createTabGroup();
	
	var win1 = Titanium.UI.createWindow({title: 'Tab 1',backgroundColor: '#fff'});
	var tab1 = Titanium.UI.createTab({title: 'Tab 1',window: win1});	
	var win2 = Titanium.UI.createWindow({title: 'Tab 2',backgroundColor: '#fff'});
	var tab2 = Titanium.UI.createTab({title: 'Tab 2',window: win2});

	var descriptionLabel = Titanium.UI.createLabel({left:20,top:20,width:Titanium.UI.FILL,font:{fontSize:12},
		   text:'PROBLEM DESCRIPTION\n'
		   +'The left nav button on the second tab (Tab 2) is invisible when the right nav button on the first tab (Tab 1) is replaced with an other button  \n\n'
		   +'STEPT TO REPRODUCE\n'
		   +'1. Switch to the second tab (Tab 2) to assure that the left nav button is visible \n'
		   +'2. Switch back to the first tab (Tab 1)\n'
		   +'3. Tap on the right nav button (Click here)\n'
		   +'4. Switch to the second tab (Tab 2) again! The left nav button is invisble\n'
		   +'5. It is possible to tap on the left nav button area (in the second tab) to fire the onClick event of the button\n\n'
		   +'ENVIRONMENT\n'
		   +'Ti Mobile SDK: 3.4.0 GA, Ti Studio: 3.4.0.201409261227, iOS: 8.1 & 8.1.1, Device: iPhone 5 and 5S'
	});
	
	win1.add(descriptionLabel);

	var leftBtn = Titanium.UI.createButton({title: 'Left'});
	var rightClickBtn = Titanium.UI.createButton({title: 'Click here'});
	var rightClickedBtn = Titanium.UI.createButton({title: 'Clicked'});
	
	leftBtn.addEventListener('click',function(){
		alert('left button clicked');
	});
	
	rightClickBtn.addEventListener('click',function(){
		win1.rightNavButton = rightClickedBtn; //toggle btn
	});
	
	win1.leftNavButton = leftBtn;
	win2.leftNavButton = leftBtn;
	
	win1.rightNavButton = rightClickBtn;
	
	tabGroup.addTab(tab1);
	tabGroup.addTab(tab2);
	
	tabGroup.open();
})();