Could you help me with hell of a weird issue?
I use Intellij IDEA 13 on Ubuntu 14.04, and from time to time my keyboard completely (yep, completely, it's not about shortcuts) locks in IDEA. I still can do anything I want in IDEA with my mouse, also I can use the keyboard everywhere else except IDEA. And it can be fixed only by restarting IDEA so far.
I've tried this out and its working so far but I'll update if it freezes up again. I've seen a suggestion on youtrack that suggests to turn off iBus which seems to interfere particularly because of it's use of the ctrl + space shortcut to change language settings. You can do that by going to:
language support > keyboard input method system > none
**** UPDATE *****
After running it for a while this technique still didn't work as I kept freezing. I guess for now I'll stick to the following workaround to restart ibus which is a bit inconvenient but what can you do.