Форма Delphi на панели задач

type
  TForm2 = class(TForm)
  private
    { Private declarations }
    procedure CreateParams(var Params: TCreateParams); override;
  end;
...

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