Behaviour of "Active topics" search on DEVNET

I use typically "Active topics" for searching of topics I have not accessed yet. In the past I have recognized very often that there were some topics shown again despite of the mutual fact that I had accessed them already.
With Volker's new Chrome app (http://qt-project.org/forums/viewthread/16100/) it is better to track.
It seems that the behavior of the search is different between top and bottom of current page. Four pictures are attached showing screen shots. First shows the entries marked with Volker's tool. Second shows same section (bottom of page) after pressing "Active topics". Third shows section with an entry. Fourth after the entry "making QPainter graphics clickable" has been read and pressing "Active topics".
Since my procedure has been a bit different from the first approach also two sequences with marking the post are included (fifth to eighth).

Just to emphasize again this behavior has nothing to do with Volker's tool.