I’m trying to change it from two eighth-notes (quaver) to a quarter note (crochet) but when I try and force the rest duration following the documentation I don’t have the ability to change the duration (or even have any controls available).
Turn on the caret, over first eighth rest, turn on force duration and the rest (,) , change to quarter note entry and a quarter rest in the triplet should appear.
(Edit, don’t know about percussion lines).
This is unfortunate. Hopefully the devs treat percussion notation like actual music notation in the future and not their idea of what percussionists need.