implicitly "see up" to a namespace from nested namespace?

This surprised me. In the Visual Studio 2017 release candidate I made a solution, put a parent POCO in a particular folder, making a default namespace like Foo.Bar.Baz, and then when I made a folder in the folder holding the parent and put some kids in there which ended up having a namespace of Foo.Bar.Baz.Qux I was able to inherit from the parent without a using declaration looping in Foo.Bar.Baz too. Interesting!