Phpstorm 6 horrible, almost unusable Javascript editing performance

Since I upgraded to Phpstorm 6 editing Javascript files was a struggle, in all sub-versions. In the best case, for any non-trivial Javascript file the IDE freezes 10-20 seconds (and maxes out 1-2 CPU cores) when I open the file, then it seems to be working ok. When I make any change in the file the editor freezes again for a few seconds. The larger the file the more horrible the experience and it happens with any Javascript files, mine or downloaded (jQuery plugins, libraries, etc). PHP or HTML files are fine, no performance issues. The hardware can't be the problem either, I'm runing on a quad 2.6GHz i7 CPU with 16GB RAM.

Any suggestions?