ArcGIS Pro 2.5: Why some fields of utility network feature classes are not editable?

Question

For example, in the screenshot below, the “isconnected” field (of the “water line” UN feature class) that is connected to the “u_5_isconnected” domain is not editable.

What could be the issue here?

JamalNUMAN · Answer

I have added new field to the waterline layer and observed that this field in not editable either.

How to make this field editable?

PaulLeBlanc1 · Answer

You must have a subnetwork controller. Update Is Connected—Utility Network Toolbox | Documentation

This attribute helps identify isolated features by maintaining whether a feature has connectivity to a subnetwork controller.

JamalNUMAN · Answer

Nothing happens as the “update is connected” tool is performed. The “is connected” field is not affected.