Как отследить изменения дисплея?

Code:

type

TForm1 = class(TForm)

Button1: TButton;

private

procedure WMDisplayChange(var Message: TMessage); message WM_DISPLAYCHANGE;

public

{ Public declarations }

end;

var

Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.WMDisplayChange(var Message: TMessage);

begin

{Do Something here}

inherited;

end;