Multiple stores URL rewrite don't work correctly.

[yssource]

Steps to reproduce

1. Install Magento from tag 2.0.7 branch.

2. Set up two stores for one website. And configure two stores with two different root categories respectively.

   Main Webstie

       USA Store --> USA Category
       Germany Store --> Germany Category
   

My categories looks like

    USA Category (root category)
          (no sub category for USA)
    Germany Category (root category)
          --- Grocery (sub category for Germany)

My default store is USA Store

1. [Example] Selecting store switcher from USA to Germany.

http://m2.dev/?___store=de_de&___from_store=en_us

1. Selecting Grocery in menu.

Expected result

1. [Example] It should correctly display Grocery category under Germany store.
2. http://m2.dev/grocery.html/?___store=de_de&___from_store=en_us

Actual result

1. [Example] 404 not found.
2. http://m2.dev/grocery.html

[yssource]

I'm sorry, it's not the issue about magento 2. Since, I have installed a extension which changed the topmenu.phtml. After disabling the extension, M2 works as expected.