Firefox Developer Edition Notes

Version 40.0a2, first offered to Firefox Developer Edition users on May 15, 2015

Check out "What’s New" and "Known Issues" for this version of Firefox below. As always, you’re encouraged to tell us what you think, or file a bug in Bugzilla. If interested, please see the complete list of changes in this release.

For more information about Developer Edition please see this MDN article and also this hacks.mozilla.org post.

What’s New

  • New

    Download protection from potentially unwanted software

  • New

    New style for add-on manager based on the in-content preferences style

  • New

    Improved scrolling, graphics, and video playback performance with off main thread compositing (Linux)

  • New

    Process separation enabled for opt-in testing

  • Changed

    Smoother animation and scrolling with hardware vsync (Windows only)

  • HTML5

    IndexedDB transactions now non-durable by default

  • HTML5

    Support for new Unicode 8.0 skin tone emoji

  • HTML5

    Implemented AudioBufferSourceNode.detune to modulate playback rate in cents

  • Developer

    New rules view tooltip to tweak CSS Filter values

  • Developer

    New page ruler highlighting tool that displays lightweight horizontal and vertical rules on a page

  • Developer

    Console API messages from SharedWorker and ServiceWorker are now displayed in web console

  • Developer

    Inspector now searches across all content frames in a page

  • Fixed

    Kannada text does not display properly in built-in pdf viewer