Release Notes for Safari Technology Preview 164

Safari Technology Preview Release 164 is now available for download for macOS Monterey 12.3 or later and macOS Ventura. If you already have Safari Technology Preview installed, you can update in the Software Update pane of System Preferences on macOS Monterey, or System Settings under General → Software Update on macOS Ventura.

This release includes WebKit changes between: 259549@main…260164@main.

Web Inspector

  • Elements tab
    • Added showing grid and flex overlays when in element selection and highlighting elements (259989@main, 260061@main)
    • Prevented showing ::backdrop rules for elements without a backdrop (259894@main)
  • Sources tab
    • Added experimental feature to enable aggressive limits on the length of lines that are formatted for sources (259603@main)


  • Fixed dynamically setting the width of tables with fixed layout and auto width (260143@main)
  • Improved serialization of mask and background properties (260157@main)
  • Made -webkit-image-set() an alias of image-set() (259994@main)
  • Made margin-trim trim collapsed margins at block-start and block-end sides (259734@main)



  • Fixed the initial last reported size of ResizeObservation (259673@main)


  • Fixed content truncation when text-overflow is ellipsis (259850@main)
  • Fixed table cells, rows, sections or column (groups) to support margins (259955@main)
  • Fixed the margin for summary on details for right-to-left mode (260063@main)
  • Fixed inline text boxes containing Zero Width Joiner, Zero Width Non-Joiner, or Zero Width No-Break Space characters to not use simplified text measuring (259618@main)

Web Animations

  • Fixed animating two custom property list values with mismatching types to use a discrete animation (259557@main)
  • Fixed the animation of color list custom properties when iterationComposite is incorrect (259761@main)
  • Fixed composite of implicit keyframes for CSS Animations to be replace (259739@main)
  • Fixed keyframes to be recomputed if a custom property registration changes (259737@main)
  • Fixed keyframes to be recomputed when bolder or lighter is used on a font-weight property (259740@main)
  • Fixed keyframes to be recomputed when a parent element changes value for a custom property set to inherit (259812@main)
  • Fixed keyframes to be recomputed when a parent element changes value for a non-inherited property set to inherit (259645@main)
  • Fixed keyframes to be recomputed when the currentcolor value is used on color related properties (259736@main)
  • Fixed keyframes to be recomputed when the currentcolor value is used on a custom property (259808@main)
  • Fixed line-height to not transition from the default value to a number (260028@main)
  • Fixed animations without a browsing context to be idle (260101@main)
  • Fixed an @keyframes rule using an inherit value to update the resolved value when the parent style changes (259631@main)
  • Fixed non-inherited custom property failing to inherit from parent when inherit is set (259809@main)


  • Fixed conditional passkey requests not cancelling correctly after AbortController.abort() (259754@main)


  • Fixed distorted audio after getUserMedia when playing with AudioWorkletNode (259964@main)
  • Fixed getDisplayMedia to not build a list of every screen and window (259969@main)


  • Enabled Clear-Site-Data HTTP header support (259970@main)
  • Added support for Clear-Site-Data: "executionContext" (259940@main)


  • Turned on the feature to make selection return a live range from getRangeAt and throw errors as specified (259904@main)
  • Fixed incorrect text caret placement when right-to-left text starts with whitespace (259868@main)


  • Added optional submitter parameter to FormData constructor (259558@main)
  • Added canvas.drawImage support for SVGImageElement (259869@main)
  • Implemented focus fixup rule so that focused elements are blurred when they are no longer focusable due to style changes (260067@main)
  • Fixed <link> elements with media queries that do not match to not block visually first paint
  • Fixed a Fetch bug with empty header values in Headers objects with “request-no-cors” guard (260066@main)
  • Fixed caret move by line when padding-top is set (259906@main)
  • Fixed individually paused or playing animations not being effected by Play All Animations and Pause All Animations (259971@main)
  • Fixed find on page failing to show results in PDFs in Safari (259655@main)
  • Fixed navigation within an iframe not exiting fullscreen for a parent iframe element (260024@main)
  • Fixed scrolling away from and back to an individually playing animation causing it to be incorrectly paused (259910@main)

Safari Web Extensions

  • Fixed Cross-Origin-Resource-Policy blocking fetch from extensions (259976@main)