Regarding the system connection checkbox.

There are two types of activity connections: manual connections and system connections. Manual connections are created by using the Connect/Disconnect Object menu option in Project Navigator/Connections, or by manually connecting the object to the activity using the Project Connection/Connect to Activity menu option on the object itself.

System connections will occur in following situations:

• When objects are created and connected directly from the project, such as a Project Miscellaneous Demand or Task created on the activity.

• When objects already connected to the activity create new objects, such as a miscellaneous demand creating a Purchase Requisition line, a Work Order creating a Purchase Order, or a Purchase Requisition line creating a Purchase Order.

• When transactions are posted with the project ID and activity sequence number, such as the transaction when registering time IFS/Project Reporting or the manual voucher row when creating a manual voucher posted with the project.

The System Connection check box indicates the type of connection for an object. Some object types can be connected both manually and by the system. Only manual connections are removable in the Connect/Disconnect Object dialog or from the object itself.

And Purchase order lines can have Both Manual & System connections depending on the business flow.