Version: VS 2017 Visual F# Tools v15.4.1.17042501

In FSX files only, Intellisense and Quick Info (hover tip) pop-ups show the type signature but not the summary documentation strings for F# core classes, modules and functions. However, the summary docs are displayed correctly for symbols defined by the user in F#, from F# libs and other .NET symbols.

Repro steps

Open an FSX file and type List.ma, or type List.map and hover over the map part.

You should see the doc string: "Builds a new collection whose elements...", but it's missing.