JabRef version 5.0-dev (commit db96f88 master) on Ubuntu-16.04 x86_64

[x ] I have tested the latest development version from * master db96f88 Fix problem with search and switching between libraries (#5326) from https://github.com/JabRef/jabref.git and the problem persists

When a bibtex database contains an entry with a keyword with only spaces in its value:

@Article{id3,
authors = {B. Kolker},
title = {Lernolibro de lingvo Esperanto},
keywords = {human > languages, , interlinguistics},
}

JabRef displays a strangely shifted empty keyword group that contains all entries:

Steps to reproduce the behavior:

1. Load the file test-empty-keword-group-BROKEN.bib or test-empty-keword-group-BROKEN2.bib (from
   test-empty-keword-group.zip) into JabRef:

build/image/bin/JabRefMain test-empty-keword-group-BROKEN.bib &

The correctly formatted file test-empty-keword-group-OK.bib behaves as expected.

The partially broken file, test-empty-keword-group-FAIR.bib, that contains an empty "keyword":

@Article{id3,
authors = {B. Kolker},
title = {Lernolibro de lingvo Esperanto},
keywords = {human > languages,, interlinguistics},
}

(note missing spaces between the two consecutive commas) is also displayed as expected.