unit Unit2a;

interface

uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, ComCtrls;

type
 TForm1 = class(TForm)
   PageControl1: TPageControl;
   TabSheet1: TTabSheet;
 private
   { Private declarations }
 public
   { Public declarations }
 end;

var
 Form1: TForm1;

implementation

{$R *.dfm}

end.

unit Unit2b;

interface

uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, Grids;

type
 TForm2 = class(TForm)
   StringGrid1: TStringGrid;
   procedure FormCreate(Sender: TObject);
 private
   { Private declarations }
   procedure CreateParams(var Params: TCreateParams); override;    
 public
   { Public declarations }
 end;

var
 Form2: TForm2;

implementation

{$R *.dfm}

uses Unit2a;

{ TForm2 }

procedure TForm2.CreateParams(var Params: TCreateParams);
begin
 inherited;
 Params.WndParent := Form1.TabSheet1.Handle;
 Params.Style := Params.Style or WS_CHILD;

end;

procedure TForm2.FormCreate(Sender: TObject);
begin
 WindowState := wsMaximized;
end;

end.