Logical data types disappear

Greetings to all

SQL Developer Version 20.2.0.175, Build 175.1842 - setting SQL Developer preferences for Data Modeller:

After exiting and restarting SQL Developer the preferred types are blank (a system types folder is set correctly).

Close of the above dialogue box creates an error: "Exception exiting traversable oracle.dbtools.crest.fcp.preferences.ModelPP[,0,0,493x405,invalid,layout=java.awt.GridBagLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=]" - I am not sure if this is related.

Has anyone any advice?

Thank you

Lindsay.