Top level windows should be centered reletive to the application's main window.

[johnwangwyx]

Good First Issue for people with some experience with the tkinter module. (Note customtkinter module used here is based on tkinter so you can still call <top_window>.geometry() or other functions just like in tkinter)

We have below top-level windows

They are currently opened from fixed positions on the screen and are not necessarily close to the application's main window (especially if the user moved the application window to another position on the screen after it is launched). We want to open them from positions relative to the main window.