question

@Viviane_B, please read about pointers as a reference to hardware memory addresses. As long as a model is not compiled and a pointer is assigned to an address they should be empty by default. A method can establish a kind of coupling between an hardware address and a model tree node, but therefore this method must be executed right from the opening of a model. You might want to insert a construct that fulfill this kind of coupling by an event like on open a model. I believe it won’t be possible to establish exactly the same computer memory address to a reloaded model on modern PCs nowadays. This was a common practice, when computers were built with an capacity of some few kilobytes and it’s System didn’t swap assembled machine code to different physical resources.