Windows 7 with IJ Ultimate 13.1.2 (just one minor minor release back from latest).
Repeatable failure mode:
(a) navigate to a project library class containing source code. E.g. i went to akka.actor.Actor
(a) select a class, method, or attribute
(b) Edit | Find | Find Usages in File .
or Edit Find | Find Usages in Project
Nothing happens.
Note: the above works fine against project files.