Swagger UI for POST /v1/security/ldap does not work

SYMPTOM:

Clicking [ Execute ] button in LDAP POST /v1/security/ldap does not do anything.

In the chrome DevTools, do not see any new request by clicking this button.

REPRODUCE STEPS:

1. Login as "admin"
2. Go to http://localhost:8081/#admin/system/api and scroll down to LDAP
3. Expand POST /v1/security/ldap and click [ Try it out ]
4. Use the default json string or type some json, then click [ Execute ]

EXPECTED BEHAVIOUR:

It should return some response

ACTUAL BEHAVIOUR:

Nothing happens, even no request to the Nexus.