Android: Navigating back from camera overlay can wrongly close the app

When a Camera activity with an overlay is opened from the first window in an application and the system's back button is pressed the application gets closed.

Test code:
app.js

var win = Ti.UI.createWindow(),

	button = Ti.UI.createButton({ title: 'Camera' });

button.addEventListener('click', function () {

	Ti.Media.showCamera({

		overlay: getOverlay()

	});

});

win.add(button);

win.open();

function getOverlay() {

	var view = Ti.UI.createView({

		backgroundColor: '#55990000',

	});

	return view;

}

Opening a camera activity from another window and clicking back works as expected - only the camera activity is closed.

One reason this may happen is that the camera activity with an overlay does not have a WindowProxy child and this raises the exitOnClose flag when we go back from it with only one window in the stack.