I had been going to General in settings also to try switching, but that's not the problem with my browser not switching between the new and old. I run noscript to block scripts in FF and if "lightboxcdn.com" is blocked, then switching between the new and old won't work. If I temporarily allow lightboxcdn, then I can switch between the two. If I further disallow lightboxcdn in noscript, it will still switch, probably due to cookies and continue to work as long as I don't close my browser. Once I close my browser, noscript will block lightboxcdn by default and again I can't switch. So the lightboxcdn.com script must be running to see the new layout... at least in FF on noscript. I'm fine with the old layout and don't care to have the ability to switch, so I'll continue to block lightboxcdn.com.