(Cross-posted from https://mathematica.stackexchange.com/q/272106/148 )
With the Default stylesheet (in Mathematica 13.1 and several versions earlier), the new kind of group opener for sections, subsections, etc., appears as in this screenshot:
When I apply a certain stylesheet to the notebook, it loses those group openers. (The stylesheet is a variant of David Park's Presentations stylesheet.)
What option(s) should I set, and with what value(s), in the Option Inspector to restore those default group openers?
