You can view comments and new answers to a question without refreshing the page. Edits don't appear until the page is refreshed. There should really be a notification or something for edits, so if you have had the question open for some time, you can see the latest versions of all posts.
The reason for this is that sometimes I will comment about an error in someone's answer, after they have corrected it. That is pretty annoying, for me and for them.
Right now it seems there is no way to view an edited post without refreshing the page. Am I right?