Safari Technology Preview 243: Accessibility, Animation, and CSS Enhancements

Accessibility Enhancements

This release addresses several key accessibility issues, particularly for users relying on assistive technologies like VoiceOver and keyboard navigation. The following fixes improve the experience for all users.

Safari Technology Preview 243: Accessibility, Animation, and CSS Enhancements — Source: webkit.org

Context menu in iframes – Fixed an issue where the contextmenu event was not fired for elements inside iframes when triggered by keyboard or assistive technology actions (e.g., VoiceOver’s VO+Shift+M). Bug #164128676.
Color picker inputs – Color picker inputs can now be activated using VoiceOver’s press action, resolving a previous limitation. Bug #172218114.
Aria-hidden invalidation – The aria-hidden="true" attribute is now properly invalidated when focus lands inside an aria-hidden subtree, ensuring assistive technology correctly reflects visibility. Bug #174449524.
Base <select> elements – VoiceOver support has been enhanced for base <select> elements, including closing the popover on selection and correcting accessibility path positioning when CSS transforms are applied. Bug #175058883.

Animation Fixes

Animations in Safari Technology Preview 243 benefit from two critical bug fixes that ensure smoother and more predictable behavior.

!important overrides – The browser now correctly honors !important declarations overriding CSS animation values when CSS transitions are also running on the same property. Bug #174367827.
Transform animations – Resolved an issue where identity matrix decomposition generated invalid quaternions, leading to incorrect transform animations. Bug #174813328.

CSS Updates

New Features

Contain: style for quote counters – Added support for contain: style applying to CSS quote counters, as specified in CSS Containment Level 2. This allows developers to limit style containment effects on generated content counters. Bug #84758186.
Text-autospace insert keyword – The text-autospace property now supports the insert keyword, providing finer control over auto-spacing behavior in text layouts. Bug #175031507.

Resolved Issues

Several CSS layout and rendering bugs have been fixed in this release, improving cross-browser compatibility and visual fidelity.

Flex layout definiteness – Fixed flex layout to use the used flex-basis instead of the specified value for definiteness evaluation, aligning with spec requirements. Bug #85707621.
Positioning with anonymous blocks – Corrected an issue where element positioning was incorrect when the containing block was an anonymous block. Bug #96548847.
Box-shadow on table-row – box-shadow now works on elements with display: table-row. Bug #96914376.
Text-indent with calc() percentages – Fixed text-indent when using calc() containing percentages: percentage components are now treated as zero for intrinsic size contributions, preventing layout misbehavior. Bug #97025949.
Out-of-flow fit-content height – Resolved an issue where out-of-flow content had an incorrect height when set to fit-content. Bug #97492632.
Percentage sizing in quirks mode flex items – Fixed an issue with percentage size resolution in flex items when running in quirks mode. Bug #100183902.
Clip-path: inset() border-radius – Corrected rendering of clip-path: inset() border-radius values at certain element and clip-path sizes. Bug #110847266.
-webkit-box flexbox in fieldset – The legacy -webkit-box flexbox emulation now correctly sizes children inside <fieldset> elements. Bug #114094538.
Performance of :where and :is – Improved performance on pages using :where and :is selectors, speeding up style recalculation. Bug #114904007.
Display: table with borders – Fixed an issue where elements with display: table could have incorrect layout when borders were present. Bug #116110440.
Border, position absolute, aspect-ratio – Resolved an issue where elements with border, position: absolute, and aspect-ratio: 1 were not rendered as squares. (Bug reference not provided in original.)

For a complete list of changes, refer to the official WebKit changelog. Safari Technology Preview continues to serve as a testing ground for upcoming WebKit features, and feedback from developers is always welcome.