- Margin.
     .Support margin if option=(Mnn) on CID header line.
      Column 1-nn is Left margin(or In-margin),(nn+1)-end of line is Right
      margin(or Out-of margin).
     .Fn[-m] option of edit command allows to set margin.
      F means fixed record length and n is record length,m is margin.
     .Bounds command set margin for some command sensitive to such margin.
     .Different display attr is set for Left and Right margin.
     .CID position can be on Left or Right margin.
      If CID is in Left margin,CID is not set for the line where data exist
      on that pos.
      If CID pos is in right margin or no margin defined,CID is appended
      when CID pos is filled by data.
      For CID CLEAR/SHIFT command,CID search range is limmited to
      the margin.
      In the case CID pos is in Left margin,it may not be right end of left
      margin. You can use the next column of CID as line continuationID column.
     .Right margin protection.
      Option is specified on CID header line like as option=(Px).
      x:0=Not protected, 1:Protected.
      (Specify like as option=(M72,P0) for multiple options)
     .Interference.
      Expansion and contraction act on the margin only,but overflow
      except space and tab from Left margin is rejected.
     .Search range specification support on Find/Change command.
      Margin can be specified as range operand.