Hi,
this is actually a reply to following:
https://moodle.org/mod/forum/discuss.php?d=269963
I could add a button to go "back to the course" inside the activity, just adding following HTML code:
<p><input id="backtocourse" value="Back to the course" onclick="location.href = '//www.yoursite.url/course/view.php?id=' + document.getElementsByTagName('body')[0].className.match('course-[0-9].').toString().slice(7)" type="button" /></p>
Maybe someone could find a more elegant solution.
Bye!