title: Multiple tkinter windows look different when closing and reopening window
body: <p>I got the following code from a tutorial. I then modified <code>main()</code> so that two windows are created as seperate threads. When I run it, only one window is created. Then when I press the <code>Quit</code> button in that window, a second window appears. In this new window the button has a different look than the first one (a look which I like better) and then if I press either of the two <code>Quit</code> buttons, both windows close and the program exits.</p>
  
  <p>Why does the second window not appear until the first <code>Quit</code> button is pressed, and why does it look different when it does appear?</p>
  
  <p>EDIT: This happens when no threads are used as well, where only one window is created at a time.</p>
  
  <p>EDIT: This is a screenshot of the two windows that are created. The one on the left is created with the program is run, the one on the right is created after clicking the "Quit" button on the first.
  <img src="https://i.stack.imgur.com/n5v5Y.png" alt="enter image description here"></p>
  
  <pre><code>from Tkinter import Tk, BOTH
  from ttk import Frame, Button, Style
  
  
  class Example(Frame):
  
      def __init__(self, parent):
          Frame.__init__(self, parent)
  
          self.parent = parent
  
          self.initUI()
  
      def initUI(self):
  
          self.parent.title("Quit button")
          self.style = Style()
          self.style.theme_use("default")
  
          self.pack(fill=BOTH, expand=1)
  
          quitButton = Button(self, text="Quit",
              command=self.quit)
          quitButton.place(x=50, y=50)
  
  
  from threading import Thread
  def main():
  
      for i in range(2):
          root = Tk()
          root.geometry("250x150+300+300")
          app = Example(root)
          Thread(target=root.mainloop()).start()
  
  
  if __name__ == '__main__':
      main()
  </code></pre>