I’m not sure what you mean by “the same calendar”. I’d like them to be. I added it to the post through [calendar][/calendar] using markup mode.
Rereading the cited document, I see now that I’ve created a “topic calendar” in the post as I’m able to add an entry using “insert date/time” in a reply.
Maybe there’s no way to do what I’m trying to do?
I was thinking something like using [calendar categoryId=123][/calendar] should do it but I don’t see that as an option in the docs.