Как отследить изменения дисплея?

Code:

type

{...}

private

   procedure WMDisplayChange(var msg: TMessage);

     message WM_DISPLAYCHANGE;

public

{...}

end;

end;

var

Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.WMDisplayChange(var msg: TMessage);

begin

ShowMessage('Display settings changed!');

inherited;

end;