I've been using IntelliJ for a while with Cursive plugin for Clojure development. A few days ago I've noticed that it started becoming very unresponsive, to the point where if I switch to a different workspace (using a tiling WM) and come back to it, IntelliJ remains a blank background colour with all the interface gone. Sometimes it repaints after a while, sometimes it just stays that way. This doesn't happen on each workspace switch, sometimes I need a few for it to happen, but in the end it surely will.
IDE itself seems to notice something's amiss, since in the log folder I get some thread dumps in folders called `freeze`, which I've uploaded as `intermittent-hangs.tar.gz` for you to review, if it helps.
I use Arch Linux, currently with 4.8.0-rc7 kernel, but this also seems to happen with older kernels (which it certainly didn't happen with before) and I don't remember updating anything big recently. This also happens for my independent WebStorm installation and with Cursive disabled as well. If there's anything else I can give to help you debug it, please do.