def synchronize(self):
        """
        Synchronize Spyder's path list with PYTHONPATH environment variable
        Only apply to: current user, on Windows platforms
        """
        answer = QMessageBox.question(self, _("Synchronize"),
            _("This will synchronize Spyder's path list with "
                    "<b>PYTHONPATH</b> environment variable for current user, "
                    "allowing you to run your Python modules outside Spyder "
                    "without having to configure sys.path. "
                    "<br>Do you want to clear contents of PYTHONPATH before "
                    "adding Spyder's path list?"),
            QMessageBox.Yes | QMessageBox.No | QMessageBox.Cancel)
        if answer == QMessageBox.Cancel:
            return
        elif answer == QMessageBox.Yes:
            remove = True
        else:
            remove = False
        from spyder.utils.environ import (get_user_env, set_user_env,
                                          listdict2envdict)
        env = get_user_env()
        if remove:
            ppath = self.active_pathlist+self.ro_pathlist
        else:
            ppath = env.get('PYTHONPATH', [])
            if not isinstance(ppath, list):
                ppath = [ppath]
            ppath = [path for path in ppath
                     if path not in (self.active_pathlist+self.ro_pathlist)]
            ppath.extend(self.active_pathlist+self.ro_pathlist)
        env['PYTHONPATH'] = ppath
        set_user_env(listdict2envdict(env), parent=self)