As of yesterday (July 21 2025), I've removed support for the "overflow: -moz-hidden-unscrollable" CSS value. This keyword was a legacy value which at this point is just an alias of "overflow: clip" (which we continue to support, and which other browsers also support). No other rendering engine ever supported "-moz-hidden-unscrollable"; it was a Mozilla-specific keyword that predated the standardization of "overflow: clip".
Bug to remove: https://bugzilla.mozilla.org/show_bug.cgi?id=1978450 This keyword has been off-by-default in Nightly for 3 years (as of https://bugzilla.mozilla.org/show_bug.cgi?id=1760734 ) with no reported problems, so it seems likely-safe to remove in general. Though: if needed, it can be reenabled by toggling about:config pref "layout.css.overflow-moz-hidden-unscrollable.enabled" to "true" (though eventually we'll remove that about:config pref, assuming the unshipping sticks.) -- You received this message because you are subscribed to the Google Groups "dev-platform@mozilla.org" group. To unsubscribe from this group and stop receiving emails from it, send an email to dev-platform+unsubscr...@mozilla.org. To view this discussion visit https://groups.google.com/a/mozilla.org/d/msgid/dev-platform/CAN_rCTkMmi6FreJKwaUpShp2HdcWMgT7LaKFtGtRkPV04G-tng%40mail.gmail.com.
