This is a patch for Multilingual assignment bug. As we discovered here
second menu not showing in multilanguage - Youjoomla Support Forums
There is small bug that prevents you from assigning menu lang menu to the template. It works ok if you use "Save & Close" but it fails on any ajax buttons.
Since YJSG 2.0.0 is in last testing phase we will not going to up the YJSG versions because of this bug.
Please just download a patch extract it and copy to your template folder.
There is only one element ( elements/yjsgupdate.php ) that has been changed.
Note that your template must be using YJSG 1.0.14 and UP