I was editing a .vtl file. I began by double-clicking a word to replace it and the double-click didn't seem do anything. After a few attempts to double-click the word I had the entire line highlighted (triple-click) then eventually I had the word highlighted. Then I pressed a letter to begin replacing the text and the IDE locked up cold. IDEA shows 372% CPU (8 core Mac Pro) usage in Activity Monitor.
Of course this isn't easily reproducible. After killing IDEA I was able to make the change.
I was able to coax three thread dumps (kill -QUIT) at few minute intervals that I've attached to this. I don't know if they'll be helpful or not.
I had this exact same problem in the previous EAP (95.24?) and my project file was corrupt (just the debugger settings luckily) after I did a force-quit.