basic inherited or vector problem?

[jacek]

Is there here a particularry purpouse?

Yes, it's because Lay::_ne is a pointer. The default copy contructor and operator= implementations will make a copy of that pointer, not the object it points to. In result Lay's destructor might delete that object more than once.

If you don't need operator= and copy constructor, you should just in case declare them as private (you can leave them unimplemented) or derive your class from boost::noncopyable.