As a new user (using Beta before purchase) I'm not sure how much user-ignorance is involved here, but...
a) moving mid-point(s) has no effect on gradient (see attached png)
b) To re-visit Gradient for editing, Help file says to Modify Gradient: with Gradient Tool selected, make Layer active, enabling editing stops, position, colours etc. But no Gradient controls appear on gradient.
Any advice on this would be welcome