You can use a folder class to organize the traffic tree. For example, you can create a folder called Critical_Apps and move all classes associated with critical applications into this folder. This structure allows you to see all your critical applications in one location in the traffic tree, plus it enables you to to create one partition to be used to protect critical traffic from other non-critical traffic.
Folder classes do not match any traffic — that is, there are no specific traffic criteria associated with this type of class. Therefore, a policy cannot be applied to a folder class. You can, however, apply a partition to a folder.
Moving folder class on both Legacy PacketShaper & S-series PacketShaper getting below error:
Specified matching rule not reachable from traffic class "ABC".
This is due to there is no matching rule on folder class. PacketShaper will verify the the matching rule on the moving class with the parent class. Since there is no matching rule define in folder class, this error is expected.