If you use a browser that allows you to open a link in a new window or new tab, use that to open the "Comment on..." link. Then, after you have composed/previewed/revised your reply and are ready to hit that "create" button, flick back to the OP window/tab and hit "reload" to see if others have replied during your labors, and if so, what they have said. Make further revisions to your epistle, or ditch it, as appropriate.

(If you don't use such a browser, it should be easy enough for you to fix that yourself... ;)