How do you 'mark messages/topics' read in this forum?

Hi, I found the keyboard shortcuts list and I can get almost all of them to work (? for help, p for user profile etc) but I don’t understand how to mark messages and/or topic as read?
I think it’s called ‘dismiss new’ on this forum, but I don’t see a button for it or a menu item, so only the keyboard shortcuts remain, but no matter if I press x,r sequentially or simulteaneously, nothing happens as far as I can tell.

Am I overlooking something here?

I usually just click the Unread tab, and click the Dismiss button, as seen here:

Does that help your issue?

Only partly, because for some reason the forum doesn’t consider topics that aren’t new to be ‘unread’ even though I haven’t read them. i.e. at the moment, there is no ‘unread’ tab, so there is no Dismiss button, but if I go to the ‘latest’ tab all the topics that aren’t new, but are unread still show up in bold, without a way to ‘mark them as read’ or ‘dismiss’ them. And for some reason that UX distracts me, because the bold type to me signifies ‘this is something that still needs your attention’.