And to expand some more - if you click the blue Reply button (at the top of the thread), you reply will appear at the end of the thread (at least in principle, there are bugs). If you click one of the black reply buttons found in each post, your reply will be posted to the end of the "sub thread" (that's the "thread" created by people replying to the same message). Because the forum does not have an indented look, this looks confusing.
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