tkinter Multiple windows (TopLevel widgets) arranging the window stack (the .lift method)

Example

The most basic case to lift a particular window above the others, just call the .lift() method on that window (either Toplevel or Tk)

import tkinter as tk #import Tkinter as tk #change to commented for python2

root = tk.Tk()

for i in range(4):
    #make a window with a label
    window = tk.Toplevel(root)
    label = tk.Label(window,text="window {}".format(i))
    label.pack()
    #add a button to root to lift that window
    button = tk.Button(root, text = "lift window {}".format(i), command=window.lift)
    button.grid(row=i)

root.mainloop()

However if that window is destroyed trying to lift it will raise an error like this:

Exception in Tkinter callback
Traceback (most recent call last):
  File "/.../tkinter/__init__.py", line 1549, in __call__
    return self.func(*args)
  File "/.../tkinter/__init__.py", line 785, in tkraise
    self.tk.call('raise', self._w, aboveThis)
_tkinter.TclError: bad window path name ".4385637096"

Often when we are trying to put a particular window in front of the user but it was closed a good alternative is to recreate that window:

import tkinter as tk #import Tkinter as tk #change to commented for python2

dialog_window = None

def create_dialog():
    """creates the dialog window
  ** do not call if dialog_window is already open, this will
     create a duplicate without handling the other
if you are unsure if it already exists or not use show_dialog()"""
    global dialog_window
    dialog_window = tk.Toplevel(root)
    label1 = tk.Label(dialog_window,text="this is the dialog window")
    label1.pack()
    #put other widgets
    dialog_window.lift() #ensure it appears above all others, probably will do this anyway

def show_dialog():
    """lifts the dialog_window if it exists or creates a new one otherwise"""
    #this can be refactored to only have one call to create_dialog()
    #but sometimes extra code will be wanted the first time it is created
    if dialog_window is None:
        create_dialog()
        return
    try:
        dialog_window.lift()
    except tk.TclError:
        #window was closed, create a new one.
        create_dialog()
    
    
root = tk.Tk()

dialog_button = tk.Button(root,
                          text="show dialog_window",
                          command=show_dialog)
dialog_button.pack()
root.mainloop()

This way the function show_dialog will show the dialog window whether it exists or not, also note that you can call .winfo_exists() to check if it exists before trying to lift the window instead of wrapping it in a try:except.

There is also the .lower() method that works the same way as the .lift() method, except lowering the window in the stack:

import tkinter as tk #import Tkinter as tk #change to commented for python2

root = tk.Tk()
root.title("ROOT")
extra = tk.Toplevel()
label = tk.Label(extra, text="extra window")
label.pack()

lower_button = tk.Button(root,
                         text="lower this window",
                         command=root.lower)
lower_button.pack()

root.mainloop()

You will notice that it lowers even below other applications, to only lower below a certain window you can pass it to the .lower() method, similarly this can also be done with the .lift() method to only raise a window above another one.