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Apple Releases Safari Technology Preview 146 Release Offers Bug Fixes and Performance Improvements

Apple Releases Safari Technology Preview 146 Release Offers Bug Fixes and Performance Improvements

Apple on Wednesday released Safari Technology Preview 146, the latest version of their developer preview web browser. The preview version of Apple’s popular browser offers developers and other interested users the ability to try out features that may or may not, debut in future public release versions of Safari.

‌Safari Technology Preview‌ release 146 includes bug fixes and performance improvements for Web Inspector, CSS, JavaScript, WebRTC, and more.

‌Safari Technology Preview‌ release 146 is built on the new Safari 15.4 update included in macOS Monterey, and as such, it includes several Safari 15 features.

The preview is available for both macOS Monterey and macOS Big Sur.

Release 146

Note: Tab Groups do not sync in this release.

Web Inspector

  • Elements Tab
    • Fixed hovering over a node in the Layout panel to now highlight it on the page (r293189)
    • Fixed <button> and <select> elements appearing in the list of Flex containers (r293565)
  • Sources Tab
    • Added ability for local overrides to entirely block a request (r293409)
  • Timelines Tab
    • Fixed importing a timeline leaves the overview non-scrollable/non-zoomable until windows is resized (r293727)
  • Graphics Tab
    • Improved display of GLenums and GLbitfield in WebGL canvas recordings. (r293541r293706)


  • Fixed ::first-letter when used in shadow content (r293497)
  • Fixed revert-layer in shadow tree contexts (r293725)
  • Fixed cascade rollback for deferred properties (r293485)
  • Related properties sharing a computed value (r293602)
  • Made word-wrap CSS property an alias of overflow-wrap (r293521)
  • Made -webkit-transform-style an alias of transform-style (r293524)
  • Unprefixed the -webkit-user-select CSS property (r293089)
  • Removed some unimplemented -webkit-appearance keywords (r293511)
  • Updated the user-agent stylesheet to include table { text-indent: initial } to conform with the HTML standard (r293322)


  • Added ISO8601 based Temporal.PlainDate getters behind a flag (r293708)
  • Enabled change-array-by-copy (r293348)
  • Fixed WASM to throw consistent exceptions for memory.init and memory.copy (r293252)
  • Fixed JS stack traces to report the correct column number in CR-LF line ending style HTML files (r293672)


  • Fixed setting the correct selection range for textarea when updating the default value (r293673)
  • Fixed constructed FormData object to not contain an entry for the submit button that was used to submit the form (r293444)
  • Fixed user-select: none to have no effect on editability (r293028)


  • Fixed the media controls overflow button flickering sometimes (r293658)
  • Fixed HTMLMediaElement getting multiple interruptions for invisible autoplay (r293609)
  • Fixed MediaSession.setPositionState() (r293488)


  • Fixed the quirk to only stretch the percent height body when it is the document element’s child (r293647)
  • Made contain: layout on the html element change position: fixed behavior (r293209)


  • Fixed smooth scrolling behavior when focusing a scroll container before beginning to scroll (r293260)


  • Fixed <link rel=preconnect> always sending credentials to a different origin, ignoring crossorigin=anonymous (r293503)

Shared Worker

  • Fixed resuming a suspended remote shared worker when a new SharedWorker object is created (r293173)

Service Worker

  • Fixed Service Worker loads to not expose some ResourceTiming information (r293418)
  • Fixed Service Worker update to refresh imported scripts in addition to the main script (r293506)
  • Fixed Service Worker to not intercept embed- or object-related loads (r293417)
  • Fixed ServiceWorkerRegistration updates to fail if called from an installing Service Worker context (r293719)
  • Fixed URL.createObjectURL to not be exposed in Service Worker contexts (r293717)


  • Fixed Web Locks held in a Worker not getting released on page refresh or exit (r293329)


  • Changed to not expose ARIA roleDescription value on “generic” elements (e.g. div and span) unless an explicit role value is also defined (r293345)


  • Fixed mixing strict-dynamic and unsafe-inline Content Security Policies (r293603)
  • Set top origin of CORS preflight requests (r293591)

While the preview is intended for use by developers and advanced users, in order to provide Apple with feedback on the development of the Safari browser, it can be run side-by-side with the release version of Safari. The app doesn’t require a developer account to download and install. For more information, visit the Safari Technology Preview website.