title: Tkinter widget opens two windows
body: <p>I am running Tkinter 3.5 on Win machine and when I run this code, I get two windows . I was expecting just one . BTW, I got the code form the web.It is working fine, except that bothers me the second(in backgorund) window .
  Basically is a widget to navigate trough different windows(pages) with buttons .</p>
  
  <pre><code>#!/usr/bin/env python
  # -*- coding: utf-8 -*-
  #
  
  try:
      import Tkinter as tk  # Python2
  except ImportError:
      import tkinter as tk  # Python3
  
  class Wizard(tk.Toplevel):
      def __init__(self, npages, master=None):
  
          self.pages = []
          self.current = 0
          tk.Toplevel.__init__(self)
  
          self.attributes('-topmost', True)
  
  
          for page in range(npages):
              self.pages.append(tk.Frame(self))
          self.pages[0].pack(fill='both', expand=1)
          self.__wizard_buttons()
  
      def onQuit(self):
          pass 
  
      def __wizard_buttons(self):
          for indx, frm in enumerate(self.pages):
              btnframe = tk.Frame(frm, bd=1, bg='#3C3B37')
              btnframe.pack(side='bottom', fill='x')
              nextbtn = tk.Button(btnframe, bd=0, bg='#F2F1F0', activebackground='#F58151', highlightcolor='red', cursor='hand2', text="Siguiente &gt;&gt;", width=10, command=self.__next_page)
              nextbtn.pack(side='right', anchor='e', padx=5, pady=5)
              if indx != 0:
                  prevbtn = tk.Button(btnframe, bd=0, bg='#F2F1F0', activebackground='#F58151', highlightcolor='red', cursor='hand2', text="&lt;&lt; Atras", width=10, command=self.__prev_page)
                  prevbtn.pack(side='right', anchor='e', padx=5, pady=5)
                  if indx == len(self.pages) - 1:
                      nextbtn.configure(text="Terminar", bd=0, bg='#F2F1F0', activebackground='#F58151', highlightcolor='red', cursor='hand2', command=self.close)
  
      def __next_page(self):
          if self.current == len(self.pages):
              return
          self.pages[self.current].pack_forget()
          self.current += 1
          self.pages[self.current].pack(fill='both', expand=1)
  
      def __prev_page(self):
          if self.current == 0:
              return
          self.pages[self.current].pack_forget()
          self.current -= 1
          self.pages[self.current].pack(fill='both', expand=1)
  
      def add_page_body(self, body):
          body.pack(side='top', fill='both', padx=6, pady=12)
  
      def page(self, page_num):
          try:
              page = self.pages[page_num]
          except KeyError("Pagina Invalida! : %s" % page_num):
              return 0
          return page
  
      def close(self):
          if self.validate():
              self.master.iconify()
              print (' TK Wizard finished... ')
              self.destroy()
              self.master.destroy()
  
      def validate(self):
          return 1 
  
  if __name__ == "__main__":
      root = tk.Tk()
      root.title(' TK Wizards ')
      wizard = Wizard(npages=3, master=root)
      wizard.minsize(400, 350)
      page0 = tk.Label(wizard.page(0), text='Pagina 1: ...Bienvenido al Wizard de TK !')
      page1 = tk.Label(wizard.page(1), text='Pagina 2: Acepta las condiciones de la WTFPL ?')
      page2 = tk.Label(wizard.page(2), text='Pagina 3: Felicitaciones, nada no se ha instalado correctamente.')
      wizard.add_page_body(page0)
      wizard.add_page_body(page1)
      wizard.add_page_body(page2)
      root.mainloop()
  </code></pre>