Add and remove rows from grid with custom container

I’ve implemented my own container class and started to use it with the new grid. I am not able to motivate the grid to react on new items in the container or on deleted ones. With the table I used
to inform the table about the changes. Obviously the grid does not register itself at the container for this events. It is only interested in

I found the problem: My container must implement ItemSetChangeNotifier. The methods of the interface are already implemented in the AbstractContainer class but they are not used until the Interface is actually implemented.