IntelliJ Ultimate 14 find usages not working

Question

I am using Intellij IDEA 14 Ultimate. When I search find usages, in find view there is a info like

Searching for usages in project files" and doesn't return any result. Scope is "whole project".

I have also IntelliJ 14 Community Edition. When it try find usages in community edition, it works.

Do you have any idea?

Answer 1

I had exactly the same problem, so for people looking for the quick answer, try

File -> Invalidate Caches / Restart

Thanks to user @yole and his comment.

Answer 2

If it doesn't solve by File -> Invalidate Caches / Restart then make sure your 'src' folder is marked as 'Sources' in project structure.