Closing a library but not JabRef, the .sav file is not deleted, causing a "Backup found" message at the next opening

[bernhard-kleine]

JabRef 5.0-dev--snapshot--2019-03-19--master--90376f40f
Windows 7 6.1 amd64
Java 1.8.0_201

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

Once I close a library clicking the +-symbol in the "Reiter", and reopened it, I get the message "Backup found" ...
Steps to reproduce the behavior:

1. Close a library by pressing the +-symbol
2. Open the same library again
3. "Backup found"

Log File

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