title: Tkinter grid manager
body: <p>I am in the process of learning Tkinter and while building general windows, frames, and all the widgets to get a feel for the interface, I ran into an issue that I can't figure out why it is behaving as is.</p>
  
  <p>I created a root window, with 3 frames and each frame has a button. The purpose of this exercise was to make sure that the frames and root window would stretch properly.</p>
  
  <p>The window and the frames do, but I noticed that the button on the first frame stays centered but the other buttons on frame 2 and 3 do not. </p>
  
  <p>I am just trying to understand why this is happening.</p>
  
  <p>Here is the code:</p>
  
  <pre><code>import tkinter as tk
  
  MW = tk.Tk()
  MW.title("TK Main Window")
  MW.config(bg='#8FBC8F',padx=5,pady=5,relief=tk.RIDGE,bd=3)
  
  FRM1 = tk.Frame(MW,bd=3,relief=tk.RIDGE,bg='#1E90FF',padx=10,pady=10)
  FRM1.grid(row=0,column=0,sticky=tk.E + tk.W + tk.N + tk.S,padx=5,pady=5)
  FRM1.rowconfigure(0,weight=1)
  FRM1.columnconfigure(0,weight=1)
  bt1 = tk.Button(FRM1, text="FRM1 button") 
  #bt1.grid(row=0,column=0,sticky=tk.W)
  bt1.grid()
  
  
  FRM2 = tk.Frame(MW,bd=3,relief=tk.RIDGE,bg='#B0C4DE',padx=10,pady=10)
  FRM2.grid(row=1,column=0,sticky=tk.E + tk.W + tk.N + tk.S,padx=5,pady=5)
  FRM2.rowconfigure(1,weight=1)
  FRM2.columnconfigure(0,weight=1)
  bt2 = tk.Button(FRM2, text="FRM2 button") 
  bt2.grid()
  
  
  FRM3 = tk.Frame(MW,bd=3,relief=tk.RIDGE,bg='#FFE4B5',padx=10,pady=10)
  FRM3.grid(row=2,column=0,sticky=tk.E + tk.W + tk.N + tk.S,padx=5,pady=5)
  FRM3.rowconfigure(2,weight=1)
  FRM3.columnconfigure(0,weight=1)
  bt3 = tk.Button(FRM3, text="FRM3 button") 
  bt3.grid()
  
  MW.rowconfigure(0,weight=1)
  MW.rowconfigure(1,weight=1)
  MW.rowconfigure(2,weight=1)
  MW.columnconfigure(0,weight=1)
  
  MW.mainloop()
  </code></pre>
  
  <p>Here is how it looks:</p>
  
  <p><img src="https://i.stack.imgur.com/6hCBC.jpg" alt="root window with 3 frames"></p>