I couldn't get my installation to work at first. Dug around a bit and realized it was because in my case the message event sent by window.opener.postMessage was received back at my main app as a jquery event, with the actual message stored at event.originalEvent. I'm not sure why this would be since I'm following the example code pretty closely. Maybe because my client is built with ui-bootstrap? In any case the fix is an easy one at my end: in the function bound to the calling window's message event, just alter event to event.originalEvent. But you may want to adjust at your end to help out other users encountering this problem.