Window.close() no longer using sliding animation / transition

I have recently upgraded a project to from Titanium SDK 2.1.4 to 3.1.1 and now my windows are no longer animating when they are closed .Is this supposed to happen? Do I need to be manually animating the windows on close()? Any help would be much appreciated. Here is a sample:

var backBtn = Ti.UI.createButton({
            title: L('home')
        });
 
        backBtn.addEventListener('click', function(e){
 
                self.close();
 
        });
 
        self.setLeftNavButton(backBtn);