Changes to fields output by comment_form in WordPress 4.4

A change in WordPress that just landed in trunk is to move the comment textarea to the top for logged-out users when replying. This is done largely with the goal to improve keyboard/focus navigation, but also aims to make it easier for end users to leave comments on WordPress sites. The change necessitated some filters and actions now being run in a different order. It also means that the HTML output by comment_form will now be different.

This is what the comment form looked like before

This is what the comment form looked like before

This is what the comment form looks like after.

If you use any of the hooks inside comment_form, but especially comment_form_field_comment and comment_form_after_fields, you are highly encouraged to test your code against the current WordPress nightly and report any issues on ticket #29974 so that any necessary adjustments can be made. Visual records and example code will help ensure everyone is satisfied with the final result.