I noticed that if I create a new topic, then delete my post (the only post in the topic), the post is removed but the topic remains and there's no way to delete it. If you try to access the topic you get the standard access denied error message:
Access denied. You must have special permissions to access this area or you are not logged in.
I'm new to Dolphn and searched for this "issue" in the forums but couldn't find anything regarding it... It's possible it's just user error on my part since I haven't used it that long.