You will see that this even goes back to Visual Studio 2012 (and possibly older) under the following circumstances:
namespace Test.Foo { using Test.Foo.Bar;
vs
using Test.Foo.Bar; namespace Test.Foo { public class Class1 { } }
The first will serialize the Test.Foo part Test.Foo. in the using statement since you are inside the namespace declaration. The second will not.
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