puh. I think this was the third attempt I tried to fix this problem. Finally, it seems to work. As so often, the problem seems usual enough and one sometimes wonders that Drupal is not better with these very common things. But, let's be more concrete.
I have a site where I want to display news. News are classified in various categories using taxonomy terms. Now, I want these categories to appear in the menu and the menu items active when I see the posts. Just common-sense functionality, one would think.
