Yicheng (Jerry) Gong

I can take a look, but just 2 things from my side: 1. From a purely performance standpoint, it seems like using [event delegation](https://javascript.info/event-delegation) here would be more ideal, e.g...

This is expected as a tradeoff for supporting `modifier`. The goal is to keep `modifier` in `beta` until it's battled tested enough before we release ` 3.0.0` supporting only `modifier`....

The direction I'm leaning toward is stop development on non-modifier, aka no more `2.x` releases and focus on `modifier`, aka `3.x` releases. Here are some reasons why `2.x` still exists...

I will reopen but I think we need some more context. Is the issue happening for the component version or modifier version or both?

For the 1st scenario, I believe you can solve the problem by adding explicit `groupName` on each `sortable-group`

@aandis thanks for the report. 1. There is an existing issue with some usages where it requires you to supply the `transition` animation in order to trigger the `transitionend` logic...

@aandis yeah good idea, I'll probably update the readme sometime soon. I'll work on #340 when I have some free time.

@aandis sorry I've been pre-occupied with other tasks. I would start by looking at the sortable-item.js, and methods like `_scrollOnEdges`.

@grapho Does `import { drag } from ember-sortable/test-helpers/drag` work? Looks like we need to re-export it from `ember-sortable-test-helpers` to make it easier.

Regardless I'll have some more time to play with this as I integrate this library into my own app. Will update the README once I figure out what final behavior...