Seems there may have been a misunderstanding, I was saying that there needs to be an option if the search is automatically updated on selection, not if it requires user action like pressing ctrl-f.
The name of the option `always_set_from_selected` suggested it was automatic, but having had a chance to look at the PR code it appears to only happen on ctrl-f (or whatever the search shortcut is set to).
If @etkaar confirms thats the case then I agree with @codebrainz it doesn't need an option, just mentioning in the manual.