Safari Technology Preview 243: Key Enhancements and Fixes

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What’s New in Safari Technology Preview 243

Apple has released Safari Technology Preview 243, the latest test version of its web browser, now available for download on macOS Tahoe and macOS Sequoia. If you already have the preview installed, you can update it via System Settings → General → Software Update. This build incorporates WebKit changes from revision 310600 to 312007, bringing a host of improvements and bug fixes. Below, we dive into the most notable updates across accessibility, animations, and CSS.

Accessibility Improvements

This release addresses several accessibility issues, making the web more usable for people relying on assistive technologies like VoiceOver.

• Context menu in iframes fixed: The contextmenu event is now properly fired for elements inside iframes when triggered by keyboard or assistive technology actions, such as VoiceOver’s VO+Shift+M. (310897@main, 164128676)
• Color picker activation: Color picker inputs can now be activated using VoiceOver’s press action, resolving a previous roadblock. (311168@main, 172218114)
• aria-hidden invalidation fixed: If focus lands inside an aria-hidden subtree, the hidden state is now correctly invalidated. (311648@main, 174449524)
• Base <select> element support: VoiceOver support for basic select elements has been enhanced, including proper popover closure on selection and correct accessibility path positioning when CSS transforms are applied. (311587@main, 175058883)

Animations: Smoother and More Predictable

Two critical animation bugs have been squashed in this release, ensuring that CSS animations and transforms behave as expected.

• !important priority restored: Fixed an issue where !important declarations were overridden by CSS animation values when CSS transitions were also running on the same property. Now, !important takes precedence as intended. (310810@main, 174367827)
• Identity matrix decomposition: Incorrect quaternions from identity matrix decomposition have been corrected. This resolves issues where transform animations produced unexpected results. (311267@main, 174813328)

CSS Enhancements and Bug Fixes

New CSS Features

Safari Technology Preview 243 introduces two new CSS capabilities:

• contain: style for quote counters: As specified in CSS Containment Level 2, the contain: style property now applies to CSS quote counters, improving performance and layout stability. (311785@main, 84758186)
• text-autospace insert keyword: The insert keyword is now supported for the text-autospace property, giving authors finer control over spacing in text. (311503@main, 175031507)

Resolved CSS Issues

Numerous layout and rendering bugs have been fixed, making pages more consistent across different scenarios.

• Flex layout definiteness: Fixed flex layout to use the used flex-basis instead of the specified value when evaluating definiteness. (311579@main, 85707621)
• Anonymous block containment: Element positioning is now correct when the containing block is an anonymous block. (311275@main, 96548847)
• Box-shadow on table-row: The box-shadow property now works properly on display: table-row elements. (310609@main, 96914376)
• Text-indent with percentage calc: text-indent with calc() containing percentages correctly treats percentage components as zero for intrinsic size contributions. (310759@main, 97025949)
• Out-of-flow fit-content height: Fixed an issue where out-of-flow content had an incorrect height when set to fit-content. (311375@main, 97492632)
• Flex items percentage size in quirks mode: Percentage size resolution in flex items now works correctly in quirks mode. (311590@main, 100183902)
• Clip-path inset border-radius: The clip-path: inset() border-radius values now render accurately at various element and clip-path sizes. (310643@main, 110847266)
• -webkit-box emulation in fieldset: Fixed -webkit-box flexbox emulation not sizing children correctly inside <fieldset> elements. (311784@main, 114094538)
• Performance improvement: Pages using :where and :is selectors now see improved performance. (311212@main, 114904007)
• Display: table with borders: Elements with display: table no longer have incorrect layout when borders are present. (311276@main, 116110440)
• Aspect-ratio square rendering: Fixed an issue where elements with border, position: absolute, and aspect-ratio: 1 were not rendered as squares. (Additional fix)

Summary of Safari Technology Preview 243

This release focuses on polishing accessibility, animation reliability, and CSS compliance. Whether you’re a web developer testing new features or an early adopter exploring macOS previews, Safari Technology Preview 243 offers a more stable and capable browsing experience. Update today to take advantage of these improvements.