anchor.diff:  function TVFDFile.GetBlocks: integer;
   var
     n: integer;
  -
     s: string;
  -
     startp, endp: integer;
     formname: string;
     bname, startmarker, endmarker: string;
     datablock: string;
     deletelen: integer;
  -
     dropmarker: boolean;
   begin
     FreeBlocks;
  -
     FParsedData := FFileData;
   
     // searching blocks:
  -
     repeat
  -
       bname     := '';
       formname  := '';
       datablock := '';
  -
  -    s      := '{@VFD_';
  +    s      := cBlockPrefix;
       startp := pos(s, FParsedData);
       if startp > 0 then
       begin
  
positive.code: //      Writeln('marker: ', startmarker);
  
        // block marker ?
  
        endmarker := '';
        if bname = 'VFD_HEAD_BEGIN' then //or (bname = 'VFD_BODY_BEGIN') then
          endmarker := '{@VFD_HEAD_END: ' + formname + '}'
  
negative.code: 
  implementation
  
  const
    cBlockPrefix = '{@VFD_';
  
  { TVFDFile }
  
  procedure TVFDFile.AddBlock(aposition: integer; ablockid, aformname, ablockdata: string);
  