Hey Free,

Dan and I were reviewing this Intent today, and I wanted to thank you 
specifically for the work that has gone into characterizing the compat 
risk. The linked Google Doc is the sort of research we'd hope to see for a 
change with such a large potential blast radius of breakage, and it does a 
lot to cabin my personal unease.

Assuming we can come to agreement on a rollout plan, LGTM1.

As a strawman proposal for rollout, how about:

  - Two or three releases enabled by default in Dev and Beta channels
  - Active DevRel outreach in this period soliciting feedback
  - ...and if all of that comes back "clean", a rollout with a kill-switch 
to disable the new behaviour should we encounter wide-scale breakage

How does that sound?

Best,

Alex

On Tuesday, August 11, 2026 at 11:26:16 AM UTC-7 Chromestatus wrote:

> *Contact emails*
> [email protected]
>
> *Explainer*
> https://github.com/explainers-by-googlers/single-axis-scroll-containers
>
> *Specification*
> https://github.com/w3c/csswg-drafts/pull/13903 
>
> *Summary*
> Extends the `overflow` property to support scrollable values together with 
> `clip` (for example, `overflow: scroll clip`). This allows `position: 
> sticky` to be constrained by different ancestor scroll containers per axis, 
> and gives authors a way to ensure an axis using `overflow: clip` stays in 
> place. 
>
> *Blink component*
> Blink>Layout 
> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ELayout%22>
>
> *Web Feature ID*
> overflow <https://webstatus.dev/features/overflow> 
>
> *Motivation*
> The CSS `overflow` property currently allows behavior to be specified per 
> axis, but it does not provide a way to make a scroll container responsible 
> for only a single axis. The affects features that depend on scroll 
> containers, namely `position: sticky` and DOM scroll APIs. For example, 
> authors may want to use `position: sticky` to create a table that keeps 
> both the top and left labels in view while the user scrolls through large 
> content. Or they may want to create a carousel that is visually clipped on 
> one axis, while ensuring that `scrollIntoView()` does not unexpectedly move 
> that clipped axis. Please see the explainer for more details. 
>
> *Initial public proposal*
> https://github.com/w3c/csswg-drafts/issues/865
>
> *TAG review*
> https://github.com/w3ctag/design-reviews/issues/1222 
>
> *TAG review status*
> Issues addressed
>
> *Goals for experimentation*
> None 
>
> *Risks*
>
>
> *Interoperability and Compatibility*
> # overflow: scroll clip overflow: scroll clip used to be converted into 
> overflow: scroll hidden, but this will no longer happen, so there is a 
> compatibility risk. Please see the analysis for more details. (
> https://docs.google.com/document/d/1_4zPKOQ8S-Ttn-4BTFaIR7YWkkQYNiF_QlTsOK-k7uE/edit?usp=sharing)
>  
>
>
> *Gecko*: No signal (
> https://github.com/mozilla/standards-positions/issues/1418)
>
> *WebKit*: No signal (
> https://github.com/WebKit/standards-positions/issues/680)
>
> *Web developers*: Positive (
> https://github.com/w3c/csswg-drafts/issues/8286) 
> https://github.com/w3c/csswg-drafts/issues/9140 
> https://github.com/w3c/csswg-drafts/issues/865
>
> *Other signals*:
>
> *WebView application risks*
>
> Does this intent deprecate or change behavior of existing APIs, such that 
> it has potentially high risk for Android WebView-based applications? 
> *No information provided* 
>
>
> *Debuggability*
> *No information provided* 
>
> *Will this feature be supported on all six Blink platforms (Windows, Mac, 
> Linux, ChromeOS, Android, and Android WebView)?*
> Yes
>
> *Is this feature fully tested by web-platform-tests 
> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?*
> Yes 
>
> https://wpt.fyi/results/?label=master&label=experimental&aligned&q=single-axis
>
> *Flag name on about://flags*
> *No information provided* 
>
> *Finch feature name*
> SingleAxisScrollContainers 
>
> *Rollout plan*
> Will ship enabled for all users
>
> *Requires code in //chrome?*
> False
>
> *Tracking bug*
> https://issues.chromium.org/440038212
>
> *Measurement*
> Usage is tracked with one broad use counter and three targeted compat 
> counters: SingleAxisScroller (
> https://chromestatus.com/metrics/feature/timeline/popularity/5862): 
> Counts every element with overflow clip on one axis and a scrollable value 
> on the other — all content this feature could affect. Note that the 
> following three have landed quite recently: 
> SingleAxisScrollerOverscrollBehavior (
> https://chromestatus.com/metrics/feature/timeline/popularity/5976): 
> Counts those elements that also set a non-auto overscroll-behavior on the 
> clip axis, where scroll chaining could change. 
> SingleAxisScrollerPositionSticky (
> https://chromestatus.com/metrics/feature/timeline/popularity/5975): 
> Counts sticky elements whose horizontal and vertical constraints now 
> resolve against different scroll containers. SingleAxisScrollerAutoMinSize (
> https://chromestatus.com/metrics/feature/timeline/popularity/5977): 
> Counts flex/grid items whose automatic minimum size now applies where it 
> previously collapsed to zero, so layout can change. The last two fire only 
> when the new behavior actually changes something, so if many sites were 
> affected it would show directly in these metrics.
>
> *Estimated milestones*
> Shipping on desktop 153 
> Shipping on Android 153 
> Shipping on WebView 153 
>
> *Anticipated spec changes*
>
> Open questions about a feature may be a source of future web compat or 
> interop issues. Please list open issues (e.g. links to known github issues 
> in the project for the feature specification) whose resolution may 
> introduce web compat/interop risk (e.g., changing to naming or structure of 
> the API in a non-backward-compatible way). 
> *No information provided*
>
> *Link to entry on the Chrome Platform Status*
> https://chromestatus.com/feature/5067363861004288?gate=6477880110481408
>
> *Links to previous Intent discussions*
> Intent to Prototype: 
> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/69b81554.050a0220.87ff1.0e40.GAE%40google.com
>
>
> This intent message was generated by Chrome Platform Status 
> <https://chromestatus.com>. 
>

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