[Plugin: NextGEN Gallery] Can't navigate in Lightbox

I just upgraded to the latest NextGEN Gallery (basic) and after playing around with the settings I cannot get the Lightbox effect in my photo galleries to work properly. If I click on an image, the Lightbox effect does pop up, but I can only see a single image instead of being able to navigate back and forth like I used to. I have tried switching from Lightbox to Thickbox and it looks exactly the same.