The only way to reply to reviews are from the View Reviews page. Although all the comments can be seen in the diffviewer/text based file attachments/screenshots, they are not organized in the review and review reply hierarchy. The comments in the comment editor dialog are also not rendered and are shown in the raw text form. Although draft review replies are shown in the comment editor textarea, it is not possible to make any changes to them. Viewing and replying to reviews will redirect the page to the View Reviews page.
This new feature will allow users to reply to reviews from the other reviews pane in the comment editor. Upon clicking on reply, the other reviews pane will expand and display the inline comment editor, similar to one in the View Reviews page. The UI for publishing and discarding review replies is more tricky and has not been determined.
The inline editor has been integrated into the other reviews pane of the comment editor dialog. If a draft reply to that comment exists, it would be shown with a green username with an edit icon beside the username. If not, the reply butoon will be displayed at the top right corner, clicking it will display the editor.
This change only allows for creating new replies to comments, publishing and discarding of review replies are only available in the View Reviews page.

Manually tested by replying to existing comments in the 3 pages - diffviewer/text based file attachments/screenshots:

- Creating new comment replies without an existing draft review reply. A new draft review reply is created with it.

- Creating new comment replies for existing draft review replies.

- Updating comment replies for existing draft review replies.