When I use 'ref' in action2 input field type, an error occurs

Hi.

When I click the API in Swagger UI which has 'ref' field in action2 inputs, it shows loading icon without finishing. I could find the error message in Swagger UI in browser dev tool.

```
Unhandled Promise Rejection: TypeError: undefined is not an object (evaluating 'B.anyOf')
```

Could you check it please?

