DropAnchor          <Alt A>
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    This command is used to mark a character Block.  Initially executing
    this command will mark one end of a Block at the cursor position.
    As the cursor is moved, the Block will "grow" with it.  Executing
    this command again will mark the other end of the Block at the
    cursor position.  If DropAnchor is executed in a file that already
    contains a character Block, the Block is extended to the current
    cursor position.