title: Tkinter not displaying label with number
body: <p>I've just started with tkinter and I ran into a problem, the label in the code below is supposed to display a rather long number (0.7522488614550792) but unfortunately it does not, the only thing visible is a little bit of the frame of the label (even when i enlarge the window), the code is not giving me any error so i'm not sure what i did wrong. Thank you for any help</p>
  
  <p>The label:</p>
  
  <pre><code>label = Label(root, textvariable=extentIndex, relief=RAISED)
  label.pack()
  </code></pre>
  
  <p>The whole code:</p>
  
  <pre><code> def select_image():
   global panelA, panelB, panelC
   path = filedialog.askopenfilename()
  
      [...]
  
      if panelA is None or panelB is None or panelC is None:
          # the first panel will store our original image
          panelA = Label(image=original)
          panelA.image = original
          panelA.pack(side="top", padx=10, pady=10)
  
          # while the second panel will store the edge map
          panelB = Label(image=binary)
          panelB.image = binary
          panelB.pack(side="right", padx=10, pady=10)
  
          panelC = Label(image=ROI)
          panelC.image = ROI
          panelC.pack(side="left", padx=10, pady=10)
  
          ###THIS IS THE LABEL###
  
          **label = Label(root, textvariable=extentIndex, relief=RAISED)
          label.pack()**
  
      # otherwise, update the image panels
      else:
          # update the pannels
          panelA.configure(image=original)
          panelB.configure(image=binary)
          panelC.configure(image=ROI)
          panelA.image = original
          panelB.image = binary
          panelC.image = ROI
  
  # initialize the window toolkit along with the two image panels
  root = Tk()
  panelA = None
  panelB = None
  panelC = None
  
  btn = Button(root, text="Select an image", command=select_image)
  btn.pack(side="bottom", fill="both", expand="yes", padx="10", pady="10")
  
  root.mainloop()
  </code></pre>