A little primer on the use of the Forum. In an existing Thread (what is started with the first post), there are 2 buttons.
The first button is
New Thread, and the second is
Post Reply.
New Thread does exactly that, it places your post into a new thread, not under the thread you have open. Therefore, Cid_cat has not seen your thread I am answering, like you wanted him to.
When you are inside an existing Thread, you need to click the Post Reply button to have your post stay in the open Thread.
I'm going to try a new feature in our newly upgraded Forum to see if I can't merge this into the prior thread.
It worked! 