Message Pop-Up Menu
  The items on the Message pop-up menu let you read,
  forward, move, delete, reply to, or extract a message, and
  reverse a move or delete action.
  Pop-up menu actions always affect the object on which MB3
  is positioned.  Pop-up menu actions do not affect other objects,
  even if they are selected.
  Additional topics:
  *   Reading the Current Message
  *   Reading the Current Message in a New Read
      Window
  *   Replying to the Current Message
  *   Forwarding the Current Message
  *   Moving the Current Message
  *   Reversing a Move or Delete Operation
  *   Deleting the Current Message
  *   Creating a File From the Current Message