When adding a new object within Advanced Lists the option to Select a Parent will only appear if the object has multiple objects that it can fit within under the List.

For example, within this List we have the following objects:
User Base (Which is our Student)

  • User Register
  • Parent/Child Relationship
  • Course Enrollment

User-added image
When Trying to add an additional User Base Object we get the pop up to select a parent:
User-added image
The options we have are:

  • User Register.Student User Id = User Base.User ID
  • Parent/Child Relationship.UserId2 = User Base.User ID
  • Course Enrollment.Student User ID = User Base.User ID

The important piece of information here is the first half of the line, stating which object will behave as the Parent. In our case, if we wanted to pull information for the Student's Parents we would want to choose Parent/Child Relationship. UserId2 = User Base.User ID, making it a parent of that object:
User-added image
In this Interaction, User Base is a Parent of the Parent/Child Relationship Object, which in itself is a Parent of the User Base Object. This can be thought of similar to a Tree, where User Base is the Stump and Parent/Child Relationship is a Branch. Any Filters we apply to that branch effect that Branch and it's stump only and do not interact with the other branches (User Register, Course Enrollment). The same is true if we wanted to delete an object from this list, if we deleted the Parent/Child Relationship object it could no longer support the User Base [1] Branch (As well as deleting any Display Fields or Filters associated to those objects)