A script that allows linking two windows together such that switching focus on one, brings up the other as well

link_windows.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Author: Sergiy Kolodyazhnyy
Date:  August 2nd, 2016
Written for: http://askubuntu.com/q/805515/295286
Tested on Ubuntu 16.04 LTS
"""
import gi
gi.require_version('Gdk', '3.0')
gi.require_version('Gtk', '3.0')
from gi.repository import Gdk, Gtk
import time
import subprocess
import sys
import argparse


def run_cmd(cmdlist):
    """ Reusable function for running shell commands"""
    try:
        stdout = subprocess.check_output(cmdlist)
    except subprocess.CalledProcessError:
        sys.exit(1)
    else:
        if stdout:
            return stdout


def focus_windows_in_order(first, second, scr):
    """Raise two user-defined windows above others.
       Takes two XID integers and screen object.
       Window with first XID will have the focus"""

    first_obj = None
    second_obj = None

    for window in scr.get_window_stack():
        if window.get_xid() == first:
            first_obj = window
        if window.get_xid() == second:
            second_obj = window

    # When this  function is called first_obj is alread
    # raised. Therefore we must raise second one, and switch
    # back to first
    second_obj.focus(int(time.time()))
    second_obj.get_update_area()
    # time.sleep(0.25)
    first_obj.focus(int(time.time()))
    first_obj.get_update_area()


def get_user_window():
    """Select two windows via mouse. Returns integer value of window's id"""
    window_id = None
    while not window_id:
        for line in run_cmd(['xwininfo', '-int']).decode().split('\n'):
            if 'Window id:' in line:
                window_id = line.split()[3]
    return int(window_id)


def main():
    """ Main function. This is where polling for window stack is done"""

    # Parse command line arguments
    arg_parser = argparse.ArgumentParser(
        description="""Linker for two X11 windows.Allows raising """ +
                    """two user selected windows together""")
    arg_parser.add_argument(
                '--quiet', action='store_true',
                help='Blocks GUI dialogs.',
                required=False)
    args = arg_parser.parse_args()

    # Obtain list of two user windows
    user_windows = [None, None]
    if not args.quiet:
        run_cmd(['zenity', '--info', '--text="select first window"'])
    user_windows[0] = get_user_window()
    if not args.quiet:
        run_cmd(['zenity', '--info', '--text="select second window"'])
    user_windows[1] = get_user_window()

    if user_windows[0] == user_windows[1]:
        run_cmd(
            ['zenity', '--error', '--text="Same window selected. Exiting"'])
        sys.exit(1)

    screen = Gdk.Screen.get_default()
    flag = False

    # begin watching for changes in window stack
    while True:

        window_stack = [window.get_xid()
                        for window in screen.get_window_stack()]

        if user_windows[0] in window_stack and user_windows[1] in window_stack:

            active_xid = screen.get_active_window().get_xid()
            if active_xid not in user_windows:
                flag = True

            if flag and active_xid == user_windows[0]:
                focus_windows_in_order(
                    user_windows[0], user_windows[1], screen)
                flag = False

            elif flag and active_xid == user_windows[1]:
                focus_windows_in_order(
                    user_windows[1], user_windows[0], screen)
                flag = False

        else:
            break

        time.sleep(0.15)


if __name__ == "__main__":
    main()