SQL Developer Ignoring NLS Preferences

I'm having and issue with SQL Developer Version 3.2.20.09 where my settings in the NLS Date and Time preferences are not being used for the nls_session_parameters.

I've changed the default Date Format to RRRR-MM-DD HH24:MM:SS in the preferences, but when I start new sessions the format remains the default set of DD-MON-RR as verified when I run

SELECT *
FROM nls_session_parameters

If I run

alter session set NLS_DATE_FORMAT = 'RRRR-MM-DD HH24:MM:SS'

I can get the information to display the way I want it to, but it resets every time I start a new session.