MarkCharacter
    -------------------------------------------------------------------------

    This command is used to mark a character Block.  It is similar to
    the DropAnchor command except the cursor position is NOT included as
    part of the Block.

    This command is provided as a replacement for the DropAnchor
    command. If you want the cursor position included in character
    Blocks, then continue to use DropAnchor; otherwise, replace the
    DropAnchor command with this command.