There seems to be some major performance problem which affects especially mac users. The problem causes the editor to freeze frequently for seconds and it is maybe most notable when a file is edited the first time. The freeze happens for all edited files (scala or nonscala) when scala plugin is enabled. The problem has been in the plugin for a while (it is present at least in version 0.2.22103), afaik the newest version that does not suffer from the problem is 0.2.21256.
Please let me know, if there is anything I can do to help fix the bug.