Mouseover tooltip on "Approve" button always tells user to "Approve this pull request"

The mouseover tooltip on the "Approve" button always displays the text "Approve this pull request (type 'a')" even if the pull request is approved. This sometimes leads to accidentaly unapproved pull-requests.

Short video clip illustrating this situation attached to this ticket (and also available directly from http://screencast.com/t/pnA2FKRrls55)