"What are the “hidden features” of the DrRacket IDE was closed as 'too localised', which surprised me as it is the IDE for popular and well regarded Lisp-family language 'Racket' previously known as PLT-Scheme.
It gets use in education and industry, and was used to implement the 'Arc' language.
The same question for Eclipse wasn't closed, and while eclipse has a large Market share, Racket is used by significant numbers of users across the globe.