Hmmm. That would be good to know if they're not actually doing anything for you. They don't take advantage of any browser-dependent code that I'm aware of, but what browser are you using?
While not impossible, the changes were to Messages.cgi (code for composing messages) and not dm.cgi (code for displaying messages), which is where the reply/peek/etc buttons are. Let me know if this continues. I don't have Safari, but I can install it and take a look.