Make Toplevel window follow root Tk window

Question

I can't find anything on this and was wondering if it was even possible.

Is there a way to make a Toplevel window follow the root Tk window when you move the Tk window across the screen?

What i do is build a Tk root window root=Tk(). Then i build the Toplevel window=Toplevel() and make the toplevel window flush with the root window on the right side. What I am curious is how to anchor the Toplevel window to the root so when i drag the root window, the Toplevel window follows.

Answer 1

You can bind to the <Configure> event of the root window, which fires when the window is moved or resized. With that you can adjust the location of the toplevel.

import tkinter as tk

class Example:
    def __init__(self):
        self.root = tk.Tk()
        label = tk.Label(self.root, text="Move me around...")
        label.pack(side="top", fill="both", expand=True, padx=20, pady=20)

        self.top = tk.Toplevel()
        label = tk.Label(self.top, text="... and I will follow!")
        label.pack(side="top", fill="both", expand=True, padx=20, pady=20)

        self.root.bind("<Configure>", self.sync_windows)

    def start(self):
        self.root.mainloop()

    def sync_windows(self, event=None):
        x = self.root.winfo_x() + self.root.winfo_width() + 4
        y = self.root.winfo_y()
        self.top.geometry("+%d+%d" % (x,y))

Example().start()