Freezes when using "Find Usages"

Hello,

I've been having these freezes lately. They definitely happened more than once when I tried to find usages of some class or method, I'm not sure if I experienced it in other cases as well.

Attached is the freeze folder I found under ~/.IntelliJIdea14/system/log/threadDumps-20150716-140102-IU-141.1532.

I'm using IDEA 14.1.4.

Thanks,

Guy