Since I updated to IJ 13.1.2 CE (on XUbuntu 13.04), I often experience a lack of responsiveness which eventually (after a few hours) makes the cursor disappear and few keystroke later, the editor ignores all keystrokes. What I do is basic editing and Shift-Ctrl-F9 to compile. If I exit IJ and restart it again, the issue disappears and will come back later.
Now go back to 13.1.1 where this issue didn't exist. Sorry for the vague report, if you need anything other info, please show me how to get that info.