[[ArdiIIa]]

Pues yo creo que simplificando y viendo la herencia, todo queda reducido a esto....

Código Delphi [-]
procedure TGraphicControl.WMPaint(var Message: TWMPaint);
begin
  if Message.DC <> 0 then
  begin
    Canvas.Lock;
    try
      Canvas.Handle := Message.DC;
      try
        Paint;
      finally
        Canvas.Handle := 0;
      end;
    finally
      Canvas.Unlock;
    end;
  end;
end;