Re: [csswg-drafts] [css-scroll-snap-1] Snap area trapping behavior of non scrollable elements (#4496)

The CSS Working Group just discussed `Snap area trapping behavior of non scrollable elements`, and agreed to the following:

* `RESOLVED: No change to scroll-snap-type, but contain:layout must trap snaps.`

<details><summary>The full IRC log of that discussion</summary>
&lt;heycam> Topic: Snap area trapping behavior of non scrollable elements<br>
&lt;heycam> github: https://github.com/w3c/csswg-drafts/issues/4496<br>
&lt;heycam> fantasai: snapping is on any descendant<br>
&lt;heycam> ... currently spec says if scroll-snap-type is non-none, it normally only applies to the scroll container<br>
&lt;heycam> ... but if you set it on a descendant element, it has the same affect as a scroll container in that snap areas in that box will no longer affect the ancestor scroll container<br>
&lt;heycam> ... Majid points out this hasn't been implemented<br>
&lt;heycam> ... this use case of wanting to trap any of these snap areas is already handeld by setting overflow to auto or hidden<br>
&lt;heycam> ... which means we can remove this<br>
&lt;heycam> fantasai: not convinced on requiriing overflow be set to do this<br>
&lt;heycam> ... but we have the contain property, which likes to contain things, maybe you want contain layout on it -- and you might want contain:layout to trap snap areas<br>
&lt;heycam> TabAtkins: yes it should<br>
&lt;heycam> fantasai: if we're implementing the possibility of trapping snap areas via contain:layout, seems to make sense we maintain the ability to have this independent switch through the scroll-snap-type property<br>
&lt;heycam> astearns: adding a value to scroll-snap-type?<br>
&lt;heycam> TabAtkins: no, it's just any value other than none<br>
&lt;heycam> TabAtkins: the idea would be there's not enough stuff depending on this not trapping<br>
&lt;heycam> heycam: I kidn of find it weird to re-use scroll-snap-type for this different meaning<br>
&lt;heycam> fantasai: you can think of it as scroll-snap-type always captures snaps<br>
&lt;heycam> fantasai: this is already in the spec<br>
&lt;heycam> ... we might want to consider re-tagging this issue against contain, so that we can make contain:layout do this snapturing<br>
&lt;heycam> RESOLVED: No change to scroll-snap-type, but contain:layout must trap snaps.<br>
</details>


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Received on Wednesday, 22 January 2020 15:15:39 UTC