Safari 27.2 Renames Grid Lanes flow-tolerance to fit-tolerance and Polishes Customizable Select

Safari 27.2 renames a Grid Lanes property and polishes Customizable Select

On October 26, the WebKit team published WebKit Features for Safari 27.2, written by Jen Simmons. The release refines Customizable Select, renames one CSS property in Grid Lanes, and fixes 20 bugs. It is a modest release, but two items change what web developers should write. Safari 27.2 ships on iOS 27.2, iPadOS 27.2, visionOS 27.2 and macOS 27.2 Golden Gate. It is also offered for macOS Tahoe and macOS Sequoia, where Safari can be updated on its own through Software Update. This is a vendor release note, and it describes behavior WebKit says it implemented, not results from outside tests.

Customizable Select gets finer styling control

Customizable Select first landed in Safari 27.0. It lets developers restyle the `<select>` drop-down control, including a `<selectedcontent>` element that controls what the closed button shows. Safari 27.2 adds a `::field-content` pseudo-element, which styles the text of the selected option without needing `<selectedcontent>`. WebKit also adjusts the default styles for `appearance: base-select`. The button contents now center vertically more reliably, the selected text inherits `text-overflow` from the `<select>`, and the picker icon is drawn with a simpler layout so that it stays visible. A large picker could previously render partly outside the viewport. Safari 27.2 keeps it in view by applying `safe` alignment, which comes from a broader CSS alignment change for absolutely and fixed positioned boxes. WebKit says the standards work continues and that other browsers are also being updated to match.

Grid Lanes: update `flow-tolerance` to `fit-tolerance`

Grid Lanes shipped in Safari 26.4. Since then the CSS Working Group renamed the `flow-tolerance` property to `fit-tolerance`, and Safari 27.2 uses the new name. The old name keeps working for now as a deprecated alias, but WebKit tells developers to update their code soon, and Safari's Web Inspector can mark what needs changing. The property sets how picky the browser is when it places the next item. If several columns end at nearly the same height, a higher tolerance treats them as tied and picks the first. The default is `1em`. WebKit argues that a higher value keeps consecutive items in neighboring columns, which makes tabbing through content steadier for sighted keyboard users, so most pages should raise it by a large amount.

Twenty bug fixes, several for agents and media

The fixes span accessibility, animation, CSS, forms, media, networking and more. Examples include VoiceOver repeating text from an `aria-live` region, `AudioContext.decodeAudioData()` failing on valid AAC/M4A files, and a frame-rate drop in WebGPU when calling `executeBundles()` on render bundles with indirect draws. One networking fix stops cookies set by a top-level navigation from being capped at seven days when the site's hostname is a CNAME to another registrable domain. One fix concerns Safari MCP: Safari no longer takes keyboard focus from other apps when software creates tabs or captures screenshots under MCP control. That detail shows that automated control of the browser is now an expected use. Developers should test any code that relied on the old behavior of these fixes, and should check browser-specific features against the notes before shipping.