anchor.diff:  var
     xev: TXEvent;
     i, n: integer;
  -  s: PChar;
  -  sl: TStrings;
   begin
     xev.xany._type       := X.ClientMessage;
     xev.xany.display     := xapplication.Display;
  
positive.code: var
    actualtype: TAtom;
    actualformat: cint;
    count, remaining, dummy: culong;
    s: TfpgString;
    data: PChar;
    lversion: culong;
  begin
  
negative.code:   child: TWindow;
    prevchild: TWindow;
  
    ret_child: TfpgWinHandle;
  
    i: integer;
    lTargetWinHandle: TWindow;
    w: TfpgX11Window;
  