I am pretty sure this isn't a _s issue but for the life of me I can't get the register_nav_menus function to work. Has anyone else had this issue?
I have only realized this after having a custom menu walker.
Please note this is an issue tracker and isn't a support forum. If you have a question about register_nav_menus I suggest to post your question to WordPress.org support forum. http://wordpress.org/support/
Once you're sure about the issue you're having is directly caused by _s then please post the issue again.