This method is identical to tkinter.simpledialog.Dialog.ok(),
        but with 'self.withdraw()' commented out.

def ok(self, event=None):
        """This method is identical to tkinter.simpledialog.Dialog.ok(),
        but with 'self.withdraw()' commented out.
        """
        if not self.validate():
            self.initial_focus.focus_set()  # put focus back
            return

        # NOTE(amin): Using self.withdraw() here causes the
        # ui to hang until the window loses and regains
        # focus. There must be some blocking operation going
        # on, but after some digging, I haven't been able to
        # get any leads.

        # NOTE(amin): We must clear the main window's entry
        # before returning focus to it. Otherwise, rapid
        # pressing of the enter key will open multiple dialogs.
        self.entry_to_clear.delete(0, 'end')

        self.update_idletasks()

        try:
            self.apply()
        finally:
            self.cancel()