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Firefox 153 release notes for developers - Mozilla | MDN
This article provides information about the changes in Firefox 153 that affect developers.
Firefox 153 was released on July 21, 2026.
developer.mozilla.org
The ::-webkit-scrollbar pseudo-element selector is now recognized, so the @supports selector(::-webkit-scrollbar) check returns true. Note that this reports the selector as supported even though scrollbar styling via ::-webkit-scrollbar is not truly implemented. This was added to fix an issue where scrollbars of nested scrollable areas could stack on top of each other. For example, when a scrollbar is set to display: none or width: 0 leaving some content unreachable. (Firefox bug 2038877).
Das Problem ist nur, Seiten mit spezifischen webkit-scrollbar Einstellungen werden damit seit v153 v.a. responsive optisch kaputt gemacht, da die Scrollbalken jetzt ein sehr merkwürdiges verhalten haben.