Messages - Icons (Missing/Incorrect Alt Tags):
While updating the Test Script for Messages on  and  using Firefox 12 - I found three icons in Messages without alt tags and one with an incorrect alt tag.
This problem exists within all four folders of Messages (Received, Sent, Deleted, & Draft).
Missing Alt Tag Icons: Mark Read, Mark Unread, & Delete.
Incorrect Alt Tag Icon: Move (current incorrect value: "Unread")
See screen capture messages_icon_alt-text.jpg.