Hi Thierry!

In the main page hover over the posts and watch your browser’s status line. I removed the http-part below (in order to prevent automatic linking).
Your first post: mylittleforum.net/forum/index.php?mode=thread&id=7095
Your second post: mylittleforum.net/forum/index.php?mode=thread&id=7095#p7096

So your first post is at the top-level; if you want to move to it, use #7095.
The second one is a reply (#7096) to the thread #7095. Therefore, you would move to #7096.

I believe in previous versions of mlf the #id was displayed in the post. For an example see my forum. It is not difficult to implement it – makes life easier.