matplotlib axis redraw on zoom

Question

I have a simple graph with a Navigation Tool Bar. When I zoom or pan, the graph is correctly updated, but the axis labels get messed up. Its as if it does not clear the old text out before drawing the new text. So you see the new text written over the old. If I resize the window, it seems to do a full re-draw and fixes the labels. Here is my simple example:

import matplotlib
matplotlib.use('TkAgg')
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, NavigationToolbar2TkAgg
from matplotlib.backend_bases import key_press_handler
from matplotlib.figure import Figure

from Tix import *
from Tkconstants import *

root = Tk()
f = Figure(figsize=(12,5), dpi=100, frameon=False)
s = f.add_subplot(111, title="test")
x = [0,1,2,3,4,5]
y = [5,2,6,7,3,6]

s.plot(x,y,label="Test")

canvas = FigureCanvasTkAgg(f, master=root)
canvas.show()
canvas.get_tk_widget().pack(side=TOP, fill=BOTH, expand=1)
canvas._tkcanvas.pack(side=TOP, fill=BOTH, expand=1)
NavigationToolbar2TkAgg(canvas, root)


root.mainloop()

Here is a before:

Here is after panning:

Answer 1

As suggested by Oblivion:
Removing the frameon=False option from f = Figure(figsize=(12,5), dpi=100, frameon=False) solved the issue.