title: Closing the window doesn't kill all processes
body: <p>I have a very simple programme that displays a simple plot on press of a button. My problem is when I close the application window, the programme keeps running until I kill it from the terminal. Below is my code and my investigation showed the issue is caused by</p>
  
  <pre><code>matplotlib.use('TkAgg')
  </code></pre>
  
  <p>But I don't know how to fix it! If it helps, I'm running on OSX.</p>
  
  <pre><code>#!/usr/bin/python
  
  from Tkinter import *
  import matplotlib
  matplotlib.use('TkAgg')
  from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
  import matplotlib.pyplot as plt
  # ------ End of imports
  
  class Ops:
      def show_plot(self):
          self.f, self.figarray = plt.subplots(1, sharex=True, sharey=True)
          self.figarray.plot((1,2,3),(1,2,3))
          plt.tight_layout()
          self.canvas = FigureCanvasTkAgg(self.f, master=self.mainFrame)
          self.canvas._tkcanvas.config(background='white', borderwidth=0, highlightthickness=0)
          self.canvas._tkcanvas.pack(side=TOP, fill=BOTH)
  
  
  class GUI(Ops):
      def __init__(self, master):
          self.master = master
          self.width = self.master.winfo_screenwidth()  # Width of the screen
          self.height = self.master.winfo_screenheight()  # Height of the screen
          self.x = (self.width / 2)
          self.y = (self.height / 2)
          self.master.geometry("%dx%d+%d+%d" % (self.width, self.height, self.x, self.y))
          self.mainFrame = Frame(self.master)  # Generate the main container
          self.mainFrame.pack()
  
          # ---------- TOP FRAME ----------
          self.topFrame = Frame(self.mainFrame)
          self.topFrame.pack()
  
          self.browse_button = Button(self.topFrame, text="Plot", command=self.show_plot)
          self.browse_button.grid()
  
  
  class App:
      def __init__(self):
          self.file_handler = Ops()
          self.root = Tk()
          self.gui_handler = GUI(self.root)
  
      def run(self):
          self.root.mainloop() 
  
  Application = App()
  Application.run()
  </code></pre>