AutoCAD 2011 introduced the CULLINGOBJ system variable that controls whether 3D subobjects that are hidden from view can be highlighted or selected. This system variable affects all objects that are behind a 3D object in one of the visual styles that masks objects, e.g, hidden, conceptual, realistic, etc.
The default value for CULLINGOBJ is 1 which means that highlighting and selection only affects the subobjects that are normal in the current view.
In this image, CULLINGOBJ is set to 1 and the back faces of 3D objects do not highlight or show grips.
In this image, CULLINGOBJ is set to 0 and the back faces and grips show for the entire object. This is similar to the behavior in AutoCAD 2010.
Changing the CULLINGOBJ system variable from 1 to 0 will restore subobject highlighting and selection to match AutoCAD 2010 behavior.