title: Python/Tkinter doesn't update label
body: <p>I am developing a password program that uses Tkinter to make it nicer and I am having some issues. The Tkinter label does not update, yet it displays the new password in the IDLE. I am still learning so please dumb it down a little bit. If you need my source code, here it is:</p>
  
  <pre><code>"""Importations"""
  import os
  
  import pygame as pygame
  from pygame import mixer
  
  import random
  
  import string
  
  import sys
  from sys import platform as _platform
  
  import tkinter as tk
  from tkinter import ttk
  
  """Program Definitions"""
  #Color Definitions
  backgroundColor = ("#001F33")
  
  #Random
  password = ("")
  
  #Font Sizes
  LARGE_FONT = ("Times", 16)
  LARGE_FONT = ("Times", 14)
  
  NORMAL_FONT = ("Times", 12)
  
  SMALL_FONT = ("Times", 10)
  XXS_FONT = ("Times", 8)
  
  """Various Functions"""
  #Quit
  def quitprog():
          sys.exit()
  
  """Class Setup"""
  #Window Setup
  class passwordGeneratorApp(tk.Tk):
  
      #Initialize
      def __init__(self, *args, **kwargs):
  
          #Container Setup
          tk.Tk.__init__(self, *args, **kwargs)
  
          tk.Tk.iconbitmap(self, default = "C:/Program Files/passGenerator/assets/images/programIcon.ico")
          tk.Tk.wm_title(self, "Random Password Generator")
  
          container = tk.Frame(self)
          container.pack(side = "top", fill = "both", expand = True)
          container.grid_rowconfigure(0, weight = 1)
          container.grid_columnconfigure(0, weight = 1)
  
          #MenuBar
          menubar = tk.Menu(container)
  
          #FileMenuBar
          filemenu = tk.Menu(menubar, tearoff = 1)
          filemenu.add_command(label = "Help", command = lambda: forhelp("For Help Contact the Following!"))
          filemenu.add_separator()
          filemenu.add_command(label = "Exit", command = quitprog)
          menubar.add_cascade(label = "File", state = "disabled", menu = filemenu)
  
          tk.Tk.config(self, menu = menubar)
  
          self.frames = {}
  
          #Pages to be Displayed
          for F in (welcomeScreen, generator):
              frame = F(container, self)
              self.frames[F] = frame
              frame.grid(row = 0, column = 0, sticky = "nsew")
              self.show_frame(welcomeScreen)
  
      #Show Frame
      def show_frame(self, cont):
  
          frame = self.frames[cont]
          frame.tkraise()
  
  """Pages"""
  #Welcome Screen
  class welcomeScreen(tk.Frame):
  
      #Initialize
      def __init__(self, parent, controller):
          tk.Frame.__init__(self, parent)
  
          welcomeScreen.configure(self, background = backgroundColor)
  
          #Generator
          def generatePass():
              char_set = string.ascii_uppercase + string.digits
              password = (''.join(random.sample(char_set*6, 6)))
              print(password)
  
          #Openning
          text_file = open("C:/Program Files/passGenerator/assets/descriptions/welcomemsg.txt", "r")
          file = text_file.read()
          text_file.close()
  
          #Setups
          titleLabel = ttk.Label(self, text = "Random Password Generator", font = LARGE_FONT)
          msgWelcome = ttk.Label(self, text = file, font = NORMAL_FONT)
          generateButton = ttk.Button(self, text = "Generate", command = generatePass)
          viewButton = ttk.Button(self, text = "View Passcode", command = lambda: controller.show_frame(generator))
  
          #Placement
          titleLabel.pack(pady = 10)
          msgWelcome.pack()
          generateButton.pack(pady = 5)
          viewButton.pack()
  
  #Generator
  class generator(tk.Frame):
  
      #Initialize
      def __init__(self, parent, controller):
          tk.Frame.__init__(self, parent)
  
          generator.configure(self, background = backgroundColor)
  
          char_set = string.ascii_uppercase + string.digits
          password = (''.join(random.sample(char_set*6, 6)))
          print(password)
  
          passwordcode = ("You're password is: %s" % password)
  
          #Setup
          titleLabel = ttk.Label(self, text = "Password Generator", font = LARGE_FONT)
          displayButton = ttk.Button(self, text = "Display Password", command = lambda: controller.show_frame(welcomeScreen))
          passwordLabel = ttk.Label(self, text = passwordcode, font = NORMAL_FONT)
  
  
          #Placement
          titleLabel.pack(pady = 5)
          displayButton.pack()
          passwordLabel.pack(pady = 5)
  
  pygame.mixer.init()   
  app = passwordGeneratorApp()
  app.geometry("1280x720")
  app.mainloop()
  </code></pre>
  
  <p>NOTE: I am running Python 3.4 on Windows.</p>