Hello JabRef team,

JabRef version 5.1 23 March 2020 on Windows 10 Intel i7 x86_64 Java 1.8.0_241

• I have tested the latest development version (5.1) from http://builds.jabref.org/master/ and the problem persists

Steps to reproduce the behavior:

1. ... load style file (select style file -> add style file)
2. ... work with your own style file
3. ...save work and close JabRef
4. ... open JabRef: added style files are missing (just the 2 internal default style files remain)

Complimentary bug:

1. ... load style file (select style file -> add style file)
2. ... work with your own style file
3. ...save work and close JabRef
4. ... open JabRef: added style files are missing (just the 2 internal default style files remain)
5. ... reload a custom style file: sometimes they are not working anymore