Dave Sailer reports:

Based on the speed of the "find usages" on methods, it seems like it ignores
class information. Say I have a class Foo and method Bar and assume Foo is
only referenced in one other class, but Bar is a method defined in many
classes. If I "find usages" on Foo, Idea responds immediately, but if I
"find usages" on Bar, it is painfully slow. I can probably grep the whole
code base faster.

Issue was resolved