The System-Workplan scope can be created between a system, which is not a workplan, and
a workplan. The system and the workplan must belong to two different root systems.
A mask
appears on the system node in the tree to indicate that there is a
scope link from the system to the workplan.
If a root system contains a system that has a scope to a workplan, it is considered as a line
balancer system. You can no longer create an item scope in this root system.
Similarly, if a root system contains a system that has a scope to an item, it cannot be considered as a line balancer system. You can
no longer create a system scope in this root system.
A check is done to ensure that there is no "crossing" system scope,
similar to what is done for a scope between an item and a system.