Bitbucket should have a way of letting a user know there are more commits

Situation:
James opens pull request, selects Frank as reviewer
Frank makes comments
James fixes comments
Frank reviews pull request and is happy with the contents
James pushes another commit
Frank's browser isn't updated and clicks the Approve button, before reviewing the last commit

Unless Frank realizes that James pushed another commit, he would have blindly approved James's last commit

Is there a workaround for this? Maybe Bitbucket should have some ajax that refreshes the pr overview page to update if a new commit is added? Or just prevents a user from approving if the screen he's looking at doesn't reflect latest commit actions?