A lot of the nice AJAX features in WP2.8 do not work under Safari 4 (on Apple client, perhaps also on other platforms).
By "do not work", I mean that the visual effect is apparent, but the underlying action is not performed. For example, if I go to the Comments page and use the "Approve" or "Spam" buttons, the entry disappears as expected but a refresh of the screen shows that nothing has happened. This works fine under Firefox.
Please perform further user tests on the Admin Panel under Safari 4, as most AJAX interfaces are broken, also in the Page/Post creation area.
I first noticed problems with the Safari 4 Beta and an earlier version of WordPress. It is possible that this is a Safari bug... but a workaround is most certainly in order if that is the case.
A sidenote... the Reporting a Bug page is very difficult to follow due to the number of links (both internally and externally). I recommend that the number of links be reduced to the bare minimum... I found myself following links to Wikipedia articles on Bugs and jumping all around the same page, when trying to find the bug tracker. After my login failed on TRAC, I ended up here.