When using Assign Zone to System Flows it is often very helpful to see other background information such as Area boundaries or fence lines to help you assign the correct zones to run together.
Actioning this management option turns most of the layers off however you can turn on the ones you require.
In IRRICAD Standalone uncheck the layer visibility in the layer bar for the required layer and then enable it again. The items will now display.
In IRRICAD Link the layers will show to be off so simply turn on the required ones, the items will now display.
The IRRICAD Team