UI Updates Round 2

@antoviaque That wouldn't quite fit the spec that was on the card, but I can do that. The spec seems to imply that, for now, the only real mode is 'random' and that other things will need to be decided before we do anything else.

Case in point, they wanted the design change to have the block named 'Randomized Content Block' by default, which implies that's the only mode.