I'm adding this post in case anyone else has discovered that Alpha's latest Build (pre-release Build 5307) has caused some serious problems with the Calendar Program" The first problem was brought to my attention by a user: When you click on an event in the Calendar, the Pop-Up display of the event is "blank" and does not show any of the correct information.
At first, I didn't realize this was caused by the latest build, but eventually, I rolled back the server to the previous build (5271) and everything started working again (without needing to do any other updates or republishing). I got the same results when I rolled back the Developer version (everything worked fine).
I also noticed that editing the component caused strange things to happen, with the new build (fields weren't saving, entries would disappear when I clicked on a field, etc.).
As I said, I'm just posting this in case anyone has had this issue, so they'd know the cause and a temporary fix. I've already sent a note to Jim Coltz and I'm sure he'll have a resolution quickly (it might be as simple as an update to the JQuery engine).