in the structure of the course page I discovered inconsistent naming:
TABLE topicsoutline TBODY TR section_0 TD topicsoutlineside TD topicsoutlinecontent TD topicsoutlineside TR TR TD topicsoutlineside TD section_1 topicsoutlinecontent TD topicsoutlineside
The first TR is named ID "section_0", the other section IDs apply to the "topicsoutlinecontent" TD. The sections cover both sides and the content. I propose to name the TR tags with the ID "section-n" with n = 0 to numer of courses (underscores can be expected critical in some browsers).