Safari Technology Preview 241: Key Updates and Bug Fixes

Introduction

Apple has released Safari Technology Preview 241, now available for download on macOS Tahoe and macOS Sequoia. Existing users can update through System Settings under General → Software Update. This release includes WebKit changes between revisions 309287@main and 310186@main, bringing a host of improvements to accessibility, animations, and CSS handling. Below, we break down the key new features and resolved issues.

Accessibility Enhancements

Resolved Issues

Several accessibility bugs have been squashed in this release:

• Speech synthesis cancellation: Calling speechSynthesis.cancel() previously removed utterances queued by subsequent speechSynthesis.speak() calls. This has been fixed, ensuring proper speech queue behavior.
• MathML table bounding boxes: Incorrect bounding boxes were computed for MathML table rows and cells, affecting screen reader navigation. This is now corrected.
• Combobox focus forwarding: Comboboxes were not forwarding focus to their aria-activedescendant, which prevented assistive technologies from interacting with list items. The issue is resolved.
• aria-owns accessibility: The aria-owns attribute was not respected when computing the accessible name from element content. This has been fixed to improve accessibility of custom widgets.

Animation Fixes

Resolved Issues

One notable animation bug has been addressed:

• animation-fill-mode with viewport units: Previously, animation-fill-mode did not correctly apply viewport-based units after the viewport was resized. This now works as expected, ensuring animations maintain their intended styling during viewport changes.

CSS Improvements

New Features

Two significant CSS features have been added:

• Stretch keyword for box sizing: The stretch keyword is now supported in box sizing properties, allowing elements to stretch to fill available space.
• CSS scroll anchoring stable support: CSS scroll anchoring now has stable support, preventing unwanted scroll jumps when content above the viewport changes.

Resolved Issues

A wide range of CSS bugs have been fixed in this release:

• Line separator rendering: The U+2028 LINE SEPARATOR is now rendered as a forced line break per the CSS specification, improving text layout.
• outline-offset inflation: On macOS, outline-offset was being inflated for outline: auto. This has been corrected.
• Font-family serialization: The serialization of font-family now preserves quotes around family names that match CSS-wide keywords or generic families.
• Unnecessary font downloads: A font was being downloaded even if no characters in the document fell within its unicode-range. This waste is eliminated.
• Flex item with percentage-height image: A flex item containing a percentage-height image did not shrink correctly around the image. This is fixed.
• View Transition snapshots color space: View Transition snapshots were incorrectly stored in sRGB, causing rendering issues with non-sRGB colors. They now use the correct color space.
• Performance with contain: layout: Using contain: layout caused significantly slower forced layouts when all siblings created their own formatting context. Performance is now improved.
• Underline splitting with ruby: Underlines were split when a ruby base was expanded due to long ruby text. This no longer occurs.
• Color-scheme repaint: Changing color-scheme did not repaint the background of composited iframes. The background now updates correctly.
• Popover element rendering: Nested children of a popover element failed to render when using position: absolute. This is resolved.
• color: initial in dark mode: Resolving color: initial to the wrong color in dark appearance mode has been fixed.
• display: contents and anchor-scope: An element with display: contents did not establish an anchor scope when using anchor-scope. This now works.
• Media query regression: A regression where media queries could fail to resolve correctly has been addressed.

Conclusion

Safari Technology Preview 241 delivers a robust set of fixes and enhancements, particularly for accessibility, animations, and CSS. Developers should update to take advantage of the improved performance and compliance. As always, the Safari Technology Preview continues to shape the future of web browsing on Apple platforms.