The optional warning C4265 is this: "'class' : class has virtual functions, but destructor is not virtual". It's supposed to warn that an instance of a derived class, if destroyed through a pointer to the base class with the non-virtual destructor, won't be destroyed correctly.
This rationale is quite sensible. However, if the class in question is a sealed class (that is, in the example at the URL above, instead of "class B" we had "class B sealed"), it can never be a base class. Therefore, there can be no instances of derived classes which wouldn't be destroyed properly through a pointer to the base class.
Shouldn't the warning, then, be disabled when the class with a virtual function but a non-virtual destructor is also marked as sealed?