Comment 5 for bug 408765

In this case, I don't think we have to distinguish that the submit button performs an AJAX action. The green link to indicate AJAX is nice where the AJAX action is unexpected; for example, opening an overlay or subscribing inline. In both those cases, the user doesn't expect those actions from clicking a link so the green may be a nice hint (although you still have to be a user fairly familiar with Launchpad to get this convention).

In the case of a "Comment" textarea and a submit button, the fact that the comment is added inline seems inconsequential to the action of submitting. By clicking a submit button, the user understands the comment will be submitted. The page can then be updated inline or could be reloaded to show the new comment and neither is a surprise to the user. So I don't think a standard submit button with the comment then added inline is a problem here.