The current behavior is that when I click >, it loads only one more message from the chain. This makes it a slow process to find previous messages without a direct link or digging around in the inbox.
Instead, those buttons should show the next page of messages, not just one. This would make scrolling through much easier and better.
Unless I'm completely mistaken. But in any case, it should be over by on page and over all the way for this to be consistent with the rest of the site.