Wut ? There's no need for Ajax to unhide a hidden Form element ? The HTML is there, and it works fine when I tell Chrome to use desktop view.
I don't expect that all replies to a post are loaded when the post is first shown (on "New Posts"). The AJAX requests loads additional replies without the need to reload the BG feed.
Thanks for letting us know. Yes we resolved it :) There was an issue where the icon in the button would ignore the event depending on how you clicked it.