JabRef version 3.3 on OSX 10.11.4

Steps to reproduce:

1. Install 3.3 on OSX, selecting to replace 3.2.
2. After installation, launch Preferences, and note that there are differences (most notably in hand-specified BibTeX key generator formats.
3. Attempt to reimport old preferences file. Choose preferences file, click OK. A dialog shows "You must restart JabRef for this to come into effect." Click OK. Click OK. ⌘-Q to Quit fully.
4. Relaunch and note that preferences are not updated.