3357708 - Unable to delete key fields of primary data source in custom CDS view - SAP S/4HANA Cloud

When trying to delete a key field of the primary data source in a custom CDS view, the "Delete" button is greyed out. 

SAP S/4HANA Cloud

Key fields of the primary data source must be included in the view.

• Elements of a custom CDS views can only be removed if they are not used.
• Key fields are an exception, as they can usually not be removed at all due to stability reasons.
• Optional the fields can be hidden in the consumption (this is an option in the element properties).
• Hiding a field will make it invisible in the final consumption runtime (e.g. in an an analytical query or in an OData service).
• Setting the hidden property will write the @Consumption.hidden annotation to the element.

Element Properties | SAP Help Portal

greyed, inactive, delete key field primary data source, disabled , KBA , BC-SRV-APS-GKE , Generic CDS Key User Editor , Problem