Thanks for your speedy reply. It was late at night when I wrote, so I tried retesting by deactivating plug-ins as you suggested. It turns out the IssueM plug-in (we run a community newspaper through our nonprofit) and the Events Calendar don’t play well together when I set IssueM to use the default WordPress categories and tags. Any thoughts on that? I’ll ask over at IssueM, too, but I was wondering if you might know where such a conflict could happen.