[csswg-drafts] [css-overscroll-1] Add an overscroll-behavior value which disables local boundary default actions (#13370)

vmpstr has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-overscroll-1] Add an overscroll-behavior value which disables local boundary default actions ==
Currently there are 3 [overscroll-behavior](https://drafts.csswg.org/css-overscroll-1/#propdef-overscroll-behavior) values:
* `auto` - which allows chaining, local and non-local boundary default actions
* `contain` - which allows local boundary default actions, but disallows chaining and non-local boundary default actions
* `none` - which disallows chaining, local and non-local boundary default actions

It would be nice to also have a value that
1. allows chaining and non-local boundary default actions
2. disallows local boundary default actions.

This would be a nice effect (or lack thereof) when bringing a side menu that shouldn't overscroll and reveal the background, but still allow scroll chaining:
e.g. https://overscroll-menu-vmpstr.yoyo.codes/

from Safari (but similar behavior on FF and Chrome Canary):

![Image](https://github.com/user-attachments/assets/135a8130-d6d8-4d3b-b58a-3c820762fa9e)

I don't have any specific suggestions for the name, but maybe something like `forward` or `continue` as a somewhat contrived opposite of `contain`

@flackr




Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/13370 using your GitHub account


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Received on Monday, 19 January 2026 21:50:15 UTC