Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

type
   TForm = class(TForm)
     {...}
   protected
     procedure CreateParams(var Params: TCreateParams); override;
   end;

 implementation

 {...}

 procedure TForm2.CreateParams(var Params: TCreateParams);
 begin
   inherited CreateParams(Params);
   Params.ExStyle   := Params.ExStyle or WS_EX_APPWINDOW;
   Params.WndParent := GetDesktopWindow;
 end;