Just a short note, the second beta of Lightning 1.2 is now available on the developer channel of addons.mozilla.org. It fixes a regression that keeps the user from saving events with attendees. If you were having trouble in the past, please do update!
Also, if you are a localizer, please note that we are nearing the final beta of Lightning 1.2. A total of 9 locales are green but have not signed off yet and 5 other locales are just missing one string for translation. I’d love to get some more locales in the Lightning 1.2 release, as right now its only 26 locales.