I think I found a bug. I played the game up until getting the teleport spell. Then I saved it and quit. I was able to load the game, but I could no longer see "cast" as an option to access my spells.
The good news is that the inventory does work as you described, and I was able to scroll down.
Oh, one more thing, I played as "Oreth the Paladin" I think ... and I found Holy Plate armor, but it was missing an equip button.
Also, after my first book journey, other character could not open blue chests, only green ones. I figure this is intended as each person seems to have special gifts, but I don't think the reasoning behind it came across so it felt buggish.