unit Unit1; interface uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls; type TForm1 = class(TForm) tbc1: TTabControl; btn1: TButton; btn2: TButton; btn3: TButton; procedure btn3Click(Sender: TObject); procedure