I have the same settings as you.

My experience is like what Barry said.

I am not sure why the dangling post you link to was left dangling. When someone deletes a post that has a reply, a place marker is left so that the replies remain part of the thread. But, if a post is deleted from the admin mode, it is completely gone and it breaks the thread, leaving a dangling post like what you experienced. My guess is that the post was a reply to a post by one of the admins who decided to delete their post and did so accidentally from the admin page rather than the regular page.

I can think of two other explanations. One would be that as computers often do, something glitched and left that post out there by itself. The other would be if I archived messages and the original message was archived and the reply was still on this board.

I believe most of the time though it will be working as you would expect.

Greg