Feature: show highlighted tab by default

[rschwarzinger]

Is your feature request related to a problem? Please describe.
In Boost Union a tab can be highlighted. The effect is a bold font that is hardly noticeable.

Describe the solution you'd like
It would be useful for teachers if the highlighting always automatically displayed the relevant tab when students accessed the course. This would save students having to search for the content currently being discussed.

Additional context
Users report that this functionality has already been implemented in the past.