Joyce - thanks for your reply. I have that setting as you suggested, but as a student I am still unable to view any assignment or score for an assignment in the student gradebook user view that has been hidden on the main course page.
I have looked through the Moodle Tracker to see if this problem has been reported, and it looks like it has, and it looks like it is listed as resolved. But I'm not experienced in deciphering what the Moodle tracker pages actually say....so I'm not sure if this problem is supposed to have been fixed in 2.3.1, or if it has been fixed in a later version, or even if it in fact has been fixed at all.
At this point, it seems my only solution is to leave everything on my main course page unhidden, so the assignments show up for the students in their gradebook view. But with courses containing dozens and dozens of graded items (if not hundreds), the main page simply becomes too long for students to easily find what they are supposed to be completing on a given day.
I am certain this was NOT the behavior of the Gradebook in 1.9....but why it would be different in 2.3.1 I don't understand.
Anyone who has a solution, even if it is a coding solution, or a tweak to role permissions, or anything else, please let me know. My teachers are gathering up their pitchforks and torches, and I am beginning to retreat to my castle.