New in v14: the mode option ('top' | 'float' | 'list' | 'compact') which replaces the old float boolean.
Same continuous re-flow as the simple list demo, but with differently sized items.
Try mode: 'compact' and drag a small item near the top: it can tuck into a gap left by a bigger item.
Try mode: 'list' instead: relative order is always preserved, so items only ever re-flow sequentially, never jump ahead.