It was my brain that was indented.
The first reply doesn't indent of course. Only replies to replies.
While we're in on Replies, I notice the reply editor has no tool in the toolbar for uploading or choosing a file. It has simple formatting tools, that's it.
I'd like them to have the same full course that the Topic post toolbar does, or at least that Choose-Or-Upload-File button.
I have tried clicking the little wrench to go to the toolbar editor, but the choose-or-upload button does not appear in the plugin list. There's a file one, an image one and lots of other things, but not that.
In my admin toolbars, it shows that forums have the full default set, and new topic post does, just the replies do not have it.
Try updating the toolbar for comments. I think forum replies are treated as comments.