Two related windows not displaying properly

Running this code on my linux mint 11 with Python 2.6 would normally lead to creating 2 windows, each of them having a frame with a Button:

from Tkinter import *

root = Tk()

boot = Toplevel()
frame = Frame(root).pack()
button = Button(frame,text="button1").pack()
fr = Frame(boot).pack()
but = Button(fr,text="button2").pack()

root.mainloop()

But running the code gives me one window (probably the root) with both buttons and another tiny window which has no frame and no button.

Copyright Notice：Content Author:「Serban Razvan」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/7189537/two-related-windows-not-displaying-properly