pro_model_item, id is not unique?
A hopefully not too dumb question.
In toolkit, in the structure pro_model_item which is used by ProDimension, ProAnnotation, ProAnnotationElem amongst others you have 3 structure members
typedef struct pro_model_item
{
ProType type;
int id;
ProMdl owner;
}
I thought the id would be unique but apparently this is not the case (e.g. a gtol and a datum tag). So I was wondering should they be unique and what is the purpose of this id?
Any help is much appreciated.

