DRAFT KB-[SP-6223] CDT shows no fields and message "Simple Types cannot be edited"

Symptoms

After modifying a CDT, the following message is observed when opened in Designer: "Simple Types cannot be edited". This can also be seen on a parent or child of the CDT that was modified.

Cause

This issue has been reported to the Appian Product Team. The reference number for this issue is AN-182130.

Workaround

To workaround the issue, perform one of the following steps:

Export the CDT from another environment, and import into the affected environment.
Delete and re-create the CDT.

Affected Versions

This article applies to Appian version 19.1 and later.