I have had 5.1 installed and something went wrong with the preview pain. It started to bring up an error looking for the admincp/commbull_textarea.php.
I noticed there was a newer version so I have installed it. I found the format has gone back from an independent button in the menu bar to one under Users. I think this is the was it was some time ago.
Any way, I liked being able to click the preview button before sending out the newsletter. That was the only reason I upgraded and it would be nice to have it back.
When I updated the settings I found there was no "Save" button. I suppose this is fine being as it saves when you click "Preview Mailing", but there is still no preview of the html