A question about class CompositionContainer

Dec 30, 2014 at 1:37 PM
I added a new an instance of CompositionContainer named C2 for a program which has been using an instance of CompositionContainer named C1. I found there are no any import classes within C2, while both they are within C1. So I've a confusion for class CompositionContainer, is there only one instance usefull within a program?