AFAIK, non-virtual methods never affect the vtable layout. But when you overload a virtual method with another virtual method, the ordering in the vtable is unspecified!
Also, a public COM interface mustn't have a virtual destructor, because some compilers (e.g. recent GCC) put more than one method in the vtable. Implementation classes might define a virtual destructor, though.
Also, a public COM interface mustn't have a virtual destructor, because some compilers (e.g. recent GCC) put more than one method in the vtable. Implementation classes might define a virtual destructor, though.