Question: What `will-change` is used for?

I see in https://github.com/bvaughn/react-window/blob/master/src/createListComponent.js#L276 that you’re using will-change: transform. But from inspecting the demos it doesn’t seems that transform is used anywhere

So, what will-change is used for?

[Romex91]

Without will-change, the scroll freezes until every item is rendered. You won’t see this on a modern CPU.

Reproduction steps on Chrome Windows:

1. Go Here
2. Ctrl+Shift+I
3. Performance->Cature Settings->CPU throttling->6x
4. Ctrl+Shift + C
5. Click the grid
6. Scroll the grid
7. Disable will-change style in Element->Styles
8. Scroll the grid again

What’s wrong:

At step 8. scrolling gets laggy.

Why bother?

The problem becomes noticeable when you have heavier items.

What about other will-change values?

@brunolemos FYI top and left produce the same effect as transform other will-change values have no effect

[SRachamim]

I suggest to reopen this issue. It adds little value and breaks fixed positions. Consider finding an alternative optimisation or not to optimise it at all.

This seems to me more like a hack than a legitimate optimisation, because will-change actually influence the visual appearance of elements.