Add CSS overscroll-behavior fix to Firefox 150 release notes (mdn#43813)

pepelsbey · web-flow · commit 12e3ce1c71f6 · 2026-04-17T14:08:41.000+02:00
* Add CSS overscroll-behavior fix to Firefox 150 release notes

* Apply suggestion
diff --git a/files/en-us/mozilla/firefox/releases/150/index.md b/files/en-us/mozilla/firefox/releases/150/index.md
@@ -53,6 +53,8 @@ Firefox 150 is the current [Beta version of Firefox](https://www.firefox.com/en-
 
 - The {{cssxref("revert-rule")}} CSS keyword is now supported. It allows a property's value to be determined as if the current style rule had not been present, so that the value from another matching rule can take effect instead. ([Firefox bug 2017307](https://bugzil.la/2017307)).
 
+- The {{cssxref("overscroll-behavior")}} CSS property (and its longhand properties {{cssxref("overscroll-behavior-x")}}, {{cssxref("overscroll-behavior-y")}}, {{cssxref("overscroll-behavior-block")}}, and {{cssxref("overscroll-behavior-inline")}}) now correctly apply to scroll containers that have no scrollable overflow, such as elements with `overflow: hidden`. Previously, the property was ignored on such elements. ([Firefox bug 1837436](https://bugzil.la/1837436)).
+
 <!-- #### Removals -->
 
 <!-- ### JavaScript -->
diff --git a/files/en-us/web/css/reference/properties/overscroll-behavior/index.md b/files/en-us/web/css/reference/properties/overscroll-behavior/index.md
@@ -128,6 +128,8 @@ In some cases, these behaviors are not desirable. You can use `overscroll-behavi
 
 Note that this property applies only to {{Glossary("Scroll_container", "scroll containers")}}. In particular, since an [`<iframe>`](/en-US/docs/Web/HTML/Reference/Elements/iframe) is not a scroll container, setting this property on an iframe has no effect. To control scroll chaining from an iframe, set `overscroll-behavior` on both the [`<html>`](/en-US/docs/Web/HTML/Reference/Elements/html) and the [`<body>`](/en-US/docs/Web/HTML/Reference/Elements/body) elements of the iframe's document.
 
+A {{Glossary("Scroll_container", "scroll container")}} that has no scrollable overflow, such as an element with `overflow: hidden`, is always considered to be at its {{Glossary("Scroll_boundary", "scroll boundary")}}. So setting a non-default `overscroll-behavior` such as `contain` or `none` on it will prevent scroll chaining to ancestor scroll containers. This can be used to prevent background scrolling while a dialog or overlay is open.
+
 ## Formal definition
 
 {{cssinfo}}
