Context action "Generate method documentation", where are you?

I work on two different solutions. In one I get for methods the extremly helpful context action "Generate method documentation", which creates an XML-comment with auto-generated text for all tags, like summary, params and return. If I change the method, for example adding params, I can run the action again and it adjusts the comment.

I don't get this context action in my other solution. I can't find anything at all about this feature. No settings in Rider, nothing in the internet, only an unresolved feature request that asks for exactly this: https://youtrack.jetbrains.com/issue/RIDER-17038?_ga=2.5295667.1605041401.1605829123-753508837.1569501092

Any idea where this "non-existent" feature is coming from and how I can make it stop to disappear?