ModelViewSet doesn't show request methods, instead it only show option button

I am using model view set and register it with router. On /docs url, it shows only option button. It doesn't show request methods(eg. GET, POST etc). Similarly on clicking plugin button, it only shows option button, not request methods. I am not able to send get request. Since it shows field required error messages.

Reproduce the issue at /docs with a Django REST Framework ModelViewSet registered through a router, then inspect how the generated controls expose request methods. Compare the ModelViewSet and plugin views, and consider the issue resolved when methods such as GET and POST are shown and a GET request can be sent without incorrect required-field errors.

Written by the indexing model from the issue text.