Assumed I need to provide a way to select items from a 2-level hierarchy. The simplest way is to have a long list of sets of checkboxes (each with a name) - that's great for discovery of the variety of items, however scrolling multiple screens up and down is not the best UX in the world.
So which is the best way to:
- Display the hierarchy in a compact way yet to be able to discover the inner items quickly enough
- See the already selected items in one place and being able to deselect them