C2RU173 Edit the `Empty` value of the repeated field '`field-name`' and then press the Apply button

Explanation
You want to switch to Edit/add another field but the repeated
field that you just added to the segment has the value
Empty.

User response
Edit the Empty value of the repeated field that was
added to the segment and press the Apply button to save all changes of the
current field. Then you can switch to another field in the current segment.