Driving me nuts.
If you are a developer on OS X and you are customer of JetBrains using IDEA the Java IDE, it is a cloudy year for you!
There are two critical bugs that haven't been fixed in over 6 months since being reported to JetBrains. IDEA enabled my fulltime switch to OS X and now it is unusable after 4 - 5 open files or half a work day. Whichever comes first.
Check it out:
Hidden editor tabs:
http://www.jetbrains.net/jira/browse/IDEA-16084
CPU spike after every compilation:
http://www.jetbrains.net/jira/browse/IDEADEV-25376
Unfortunately, there is no viable workaround.
Come on JetBrains! Fix it!