Alas, as the post has been redirected etc., User A no longer has a proper place to put a reply!
User B’s reply is still visible, and User A wants to reply to it but no longer can find a proper place. Any place that User A can think of to post a reply would now be too far off topic in the newly connected threads.
So, maybe when threads get redirected etc., the software should make sure there are still reply buttons that will direct to the official place one is supposed to reply to.
OK, quoting worked. But then I see I’m about to “Create a new Topic”. That would get me in big trouble. As the moderators took all the trouble to redirect the discussion, and there I am wanting to split it off again.
As to oneboxing,
OK, one day I will research what that is all about.
I find opening the reply composer in the topic I want to reply to and then navigating to the topic(s)/post(s) I wish to quote is a good flow.
Though the new ‘copy quote’ button allows you to copy the quote along with the correct quote formatting to paste it into your reply if you want to do it the opposite way round.
If you’re looking for beginner tips like oneboxing you can do the Discobot tutorial or possibly look at the Discourse New User Guide?