why does a disabled button respond to clicks

[damonjulian at yahoo.com]

hi ,i created 3 buttons such that if button1 is clicked it will
disable button2 ,and clicking button3 will restore state of button2 to
normal,

to my dismay i find that button2 still responds to clicks even if it
is greyed out

here is the code..am i doing something wrong? is there a way to truly
disable the button?



class MyApp:
	def __init__(self,parent):
		self.mainframe=Frame(parent)
		self.mainframe.pack()

		#self.canvorig=Canvas(self.mainframe,width=100,height=200)
		#self.canvorig.pack()
		self.button1=Button(self.mainframe,bg="green")
		self.button1.configure(text="1")
		self.button1.pack(side=LEFT)
		self.button1.bind("<Button-1>",self.buttonClick1)
		self.button2=Button(self.mainframe,bg="yellow")
		self.button2.configure(text="2")
		self.button2.pack(side=LEFT)
		self.button2.bind("<Button-1>",self.buttonClick2)
		self.button3=Button(self.mainframe,bg="red")
		self.button3.configure(text="3")
		self.button3.pack(side=RIGHT)
		self.button3.bind("<Button-1>",self.buttonClick3)

	def buttonClick1(self,event):
		print "ok clicked"
		self.button2.configure(state="disabled")
		self.button2.update_idletasks()

	def buttonClick2(self,event):
		print "2 clicked"

	def buttonClick3(self,event):
		print "3 clicked"
		self.button2.configure(state="normal")
		self.button2.update_idletasks()

root = Tk()
myapp = MyApp(root)
root.mainloop()