The new style visualizers defined in
C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\Packages\Debugger\Visualizers\defaultvis.natvis
for elements of the C++ Standard Library have incorrectly defined Type Name attributes.
These definitions refer to std::tr1 whereas the types in Visual Studio 11 are now defined in std:: but not aliased from std::tr1 as it is in Visual Studio 2010.
So, for instance
The incorrect references to std::tr1:: lead to lack of proper visualization while debugging.