Включить Drop Shadow Effect окна в XP

type
TForm1 = class(TForm)
protected
procedure CreateParams(var Params: TCreateParams); override;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.CreateParams(var Params: TCreateParams);
const
CS_DROPSHADOW = $00020000;
begin
inherited;
Params.WindowClass.Style := Params.WindowClass.Style or CS_DROPSHADOW;
end;