CORS OriginList not shown in UI

Running Traefik 2.2.0. Need to define some CORS Header:

apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
name: longhorn-cors
namespace: default
spec:
headers:
accessControlAllowMethods:
- "GET"
- "OPTIONS"
- "PUT"
accessControlAllowOriginList:
- "http://localhost"
accessControlMaxAge: 100
addVaryHeader: "true"

Dashboard does not show OriginList. Is this an UI-issue only? Or was OriginList not accepted for any reason?
Thanks,
Wolfram