Python/Tkinter root window background configuration

Question

I'm trying to create a root window with a black background to blend with my button backgrounds.

I have the following:

class Application(Frame):
    def __init__(self, parent):
        Frame.__init__(self, parent)
        self.parent = parent
        self.initUI()
...

    def initUI(self):
        self.outputBox = Text(bg='black', fg='green', relief=SUNKEN, yscrollcommand='TRUE')
        self.outputBox.pack(fill='both', expand=True)
        self.button1 = Button(self, text='button1', width=40, bg ='black', fg='green', activebackground='black', activeforeground='green')
        self.button1.pack(side=RIGHT, padx=5, pady=5)
        self.button2 = Button(self, text='button2', width=20, bg='black', fg='green', activebackground='black', activeforeground='green')
        self.button2.pack(side=LEFT, padx=5, pady=5)
...

def main():
    root = Tk()   
    root.geometry('1100x350+500+300')
    root.configure(background = 'black')
    app = Application(root)
    root.mainloop()  

But root.configure(background = 'black') isn't changing the root window's background color... any suggestions?

Solution

This works (Check how parent root is referenced):

Edit: I edited the code and figure to make clear where colors are set:

from Tkinter import *

class Application(Frame):
    def __init__(self, master=None):
        Frame.__init__(self, master)
        self.parent = master
        self.initUI()

    def initUI(self):
        self.outputBox = Text(self.parent, bg='yellow', height= 10, fg='green', relief=SUNKEN, yscrollcommand='TRUE')
        self.outputBox.pack(fill='both', expand=True)
        self.button1 = Button(self.parent, text='button1', width=20, bg ='blue', fg='green', activebackground='black', activeforeground='green')
        self.button1.pack(side=RIGHT, padx=5, pady=5)
        self.button2 = Button(self.parent, text='button2', width=25, bg='white', fg='green', activebackground='black', activeforeground='green')
        self.button2.pack(side=LEFT, padx=5, pady=5)

def main():
    root = Tk()
    app = Application(root)
    app.parent.geometry('300x200+100+100')
    app.parent.configure(background = 'red')
    app.mainloop()

main()