JabRef 5.1--2020-05-02--1d9957b
Linux 5.6.8-200.fc31.x86_64 amd64
Java 14.0.1

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

In a test database with >10500 entries, add an entry (ctrl n, or with button): this crashes jabref. No log message.

In a smaller database, no problem adding a new entry. I can copy and paste it into the larger database.