[roman]

Intercepta el mensaje WM_SYSCOMMAND:

Código Delphi [-]
interface

type
  TForm1 = class(TForm)
  private
    procedure WMSysCommand(var Msg: TWMSysCommand);
  end;

implementation

procedure TForm1.WMSysCommand(var Msg: TWMSysCommand);
begin
  if (Msg.CmdType and $FFF0 = SC_MAXIMIZE) then
  begin
    // Mostrar componente
  end
  else if (Msg.CmdType and $FFF0 = SC_RESTORE)
  begin
    // Ocultar componente
  end;

  inherited;
end;

LineComment Saludos