Safari Technology Preview 243: Enhanced Accessibility, CSS Improvements, and More

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Safari Technology Preview 243 is now available for download on macOS Tahoe and macOS Sequoia. If you already have the preview installed, you can update it in System Settings under General → Software Update. This release includes WebKit changes between build numbers 310600@main and 312007@main, bringing a variety of bug fixes and new features across accessibility, animations, and CSS.

Accessibility Enhancements

Several accessibility issues have been resolved to improve the user experience for those relying on assistive technologies like VoiceOver.

• Contextmenu Event in iframes: Fixed an issue where the contextmenu event was not fired for elements inside iframes when triggered by keyboard or assistive technology actions such as VoiceOver’s VO+Shift+M. (310897@main)
• Color Picker Activation: Color picker inputs can now be activated using VoiceOver’s press action, resolving a previous roadblock. (311168@main)
• Aria-Hidden Invalidation: The invalidation of aria-hidden="true" when focus lands inside the aria-hidden subtree has been fixed, ensuring hidden content remains properly ignored by assistive technologies. (311648@main)
• Base Select Elements: VoiceOver support for base <select> elements has been improved, including proper closing of the popover on selection and correct accessibility path positioning when CSS transforms are applied. (311587@main)

Animation Fixes

Two important animation issues have been addressed in this release.

• !important vs. Transitions: Fixed an issue where !important declarations did not override CSS animation values when CSS transitions were also running on the same property. This ensures that explicit !important rules take precedence as expected. (310810@main)
• Identity Matrix Decomposition: Fixed an issue where identity matrix decomposition generated invalid quaternions, leading to incorrect transform animations. Animations now behave correctly with identity transforms. (311267@main)

CSS Updates

New Features

Two new CSS capabilities have been added.

• Contain: Style for Quote Counters: Added support for contain: style applying to CSS quote counters, as specified in CSS Containment Level 2. This improves performance and predictability when using counters inside containment contexts. (311785@main)
• Insert Keyword for text-autospace: The insert keyword for the text-autospace property is now supported, giving developers finer control over automatic spacing in text. (311503@main)

Resolved Issues

A wide range of CSS bugs have been fixed, enhancing layout correctness and performance.

• Flex Layout Definiteness: Fixed flex layout to use the used flex-basis instead of the specified value for definiteness evaluation. This ensures more accurate sizing in flex containers. (311579@main)
• Anonymous Block Positioning: Fixed an issue where element positioning was incorrect when the containing block was an anonymous block. (311275@main)
• Box-Shadow on Table-Row: box-shadow now works correctly on display: table-row elements. (310609@main)
• Text-Indent with Calc: text-indent using calc() with percentages now correctly treats percentage components as zero for intrinsic size contributions. (310759@main)
• Out-of-Flow Height with fit-content: Fixed an issue where out-of-flow content had an incorrect height when set to fit-content. (311375@main)
• Percentage Size in Flex Items (Quirks Mode): Corrected an issue with percentage size resolution in flex items when in quirks mode. (311590@main)
• Clip-Path Inset Border-Radius: Fixed an issue where clip-path: inset() border-radius values did not render correctly at certain element and clip-path sizes. (310643@main)
• -webkit-box Flexbox Emulation in Fieldset: Fixed -webkit-box flexbox emulation not sizing children correctly inside <fieldset> elements. (311784@main)
• Performance with :where and :is: Improved performance on pages using :where and :is selectors by optimizing evaluation. (311212@main)
• Display: Table Layout with Borders: Fixed an issue where elements with display: table could have incorrect layout when borders were present. (311276@main)
• Aspect-Ratio with Border and Absolute: Corrected an issue where elements with border, position: absolute, and aspect-ratio: 1 were not rendered as squares. (No bug ID provided in original, but addressed in this release.)

For the complete list of changes, refer to the official WebKit commit log. Download Safari Technology Preview 243 today and experience a smoother, more reliable browsing experience on macOS.

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