auto-remove-sublime-license-popup

#!/usr/bin/python
# -*- coding: utf-8 -*-

import sublime_plugin
import subprocess
from time import sleep
import sys
 
cl = lambda line: subprocess.Popen(line, shell=True, stdout=subprocess.PIPE).communicate()[0].strip()
log = lambda message: sys.stderr.write("Log: %s\n" % message)
 
sublimeMainWindowTitle = " - Sublime Text (UNREGISTERED)"
 
class LicenseWindowKiller(sublime_plugin.EventListener):
 
    def seek_n_close(self):
        sublimePid = int(cl("""wmctrl -lp | grep "%s" | awk '{print $3}'""" % sublimeMainWindowTitle).decode())
        if sublimePid:
            sublimeMainWindowId = cl("""wmctrl -lp | grep "%s" | awk '{print $1}'""" % sublimeMainWindowTitle).decode()
            sublimeSecondWindowId = cl("""wmctrl -lp | grep %s | awk '{ids[$1]++}{for (id in ids){if (id != "%s"){printf id}}}'""" % (sublimePid, sublimeMainWindowId)).decode()
            if sublimeSecondWindowId:
                sublimeSecondWindowTitle = cl("""wmctrl -lp | grep %s | awk '{print $5}'""" % sublimeSecondWindowId).decode()
                if not sublimeSecondWindowTitle:
                    cl("wmctrl -i -c %s" % sublimeSecondWindowId)
                    return True
        return False
 
    def on_pre_save_async(self, *args):
        seek = True
        counter = 10
        while seek:
            sleep(.5)
            counter -= 1
            if counter < 0:
                seek = False
            seek = not self.seek_n_close()

thats work in sublime Text 3?

Give this version a try... tested on Linux:
https://gist.github.com/ruped24/a0fd0272a8ef56441cafb44c753310e0