Ordinarily, transitions will play on elements when any container block is added or destroyed. In the example here, toggling the visibility of the entire list also applies transitions to individual list elements.
Ordinarily, transitions will play on elements when any container block is added or destroyed. In the example here, toggling the visibility of the entire list also applies transitions to individual list elements. Notice how the list doesn't slide when you toggle the checkbox with the *local* transition, instead it pops in and out.
Instead, we'd like transitions to play only when individual items are added and removed — in other words, when the user drags the slider.