Code:

procedure TMyForm.CreateParams(var Params :TCreateParams); {override;}

begin

inherited CreateParams(Params); {CreateWindowEx}

Params.ExStyle := Params.ExStyle or WS_Ex_AppWindow;

end;

Code:

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;

Code:

uses Unit2, Unit3;

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);

begin

ShowWindow(Application.Handle, SW_HIDE);

Form1.Hide;

Form2.Show;

Form3.Show;

end;

Code:

uses Unit3;

{$R *.DFM}

procedure TForm2.FormCreate(Sender: TObject);

begin

SetWindowLong(Handle, GWL_EXSTYLE,

GetWindowLong(Handle, GWL_EXSTYLE) or WS_EX_APPWINDOW);

end;

procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);

begin

if Form3.Visible = false then

   Application.Terminate;

end;

Code:

uses Unit2;

{$R *.DFM}

procedure TForm3.FormCreate(Sender: TObject);

begin

SetWindowLong(Handle, GWL_EXSTYLE,

GetWindowLong(Handle, GWL_EXSTYLE) or WS_EX_APPWINDOW);

end;

procedure TForm3.FormClose(Sender: TObject; var Action: TCloseAction);

begin

if Form2.Visible = false then

   Application.Terminate;

end;

Code:

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;