Multiple shops one shopping cart is not working

I have created in magento 2 shops with 1 common shopping cart. If I am a visitor an开发者_开发知识库d add to cart 1 product from 1st store and then go to 2nd store the cart reset.I saw on gap.com that this work. Anybody can help me with this problem?

See this article: Magento's multi-storefront implementation is half-baked http://www.magthemes.com/magento-blog/magento-fully-support-multistore-functionality/

How gap.com set up the multiple stores with single checkout is explained in these webinars