When working with Publication and Subscription services, if a custom IDOC is being used, it is seen that the custom IDOC is visible in the Fetched Result List, but the schema related to the custom IDOC is not visible in the Designer when fetching, and the "Refresh Schema" tab is disabled.

Cause: The user logged into Designer, in order to fetch the IDOC, does not have proper authorization to view the IDOC definitions. If a custom IDOC was created by "User A", and the Designer was assigned to "User B", then there may be a possibility that "User B" does not have the required permission to view the IDOC definition.