JabRef version 5.0dev (latest) on Windows 10

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

In case you add an entry externally and check the change in the review dialog a NullPointerException is thrown.

Steps to reproduce the behavior:

1. Open a bib file.
2. Add an entry in external text editor
3. Review change "Added Entry"

java.lang.NullPointerException: null
  at java.util.Objects.requireNonNull(Objects.java:203) ~[?:1.8.0_121]
  at org.jabref.gui.PreviewPanel.<init>(PreviewPanel.java:90) ~[classes/:?]
  at org.jabref.gui.collab.EntryAddChangeViewModel.description(EntryAddChangeViewModel.java:32) ~[classes/:?]
  at org.jabref.gui.collab.ChangeDisplayDialog.selectedChangeChanged(ChangeDisplayDialog.java:77) ~[classes/:?]
  at org.fxmisc.easybind.EasyBind.lambda$subscribe$12(EasyBind.java:263) ~[easybind-1.0.3.jar:?]

Reason is quite obvious as a null database context is passed to PreviewPanel constructor which is stating: Objects.requireNonNull(databaseContext);

Apart from EntryAddChangeViewModel also EntryDeleteChangeViewModel is affected