I cannot merge entries with the same key

[ilippert]

JabRef version

Latest development branch build (please note build date below)

Operating system

GNU / Linux

Details on version and operating system

JabRef 5.5--2022-01-09--7d4916e Linux 5.15.13-200.fc35.x86_64 amd64 Java 16.0.2 JavaFX 17.0.1+1

Checked with the latest development build

• I made a backup of my libraries before testing the latest development version.
• I have tested the latest development version and the problem persists

Steps to reproduce the behaviour

1. generate several copies of the same entry (say, 2 entries with the same key) (see deleting entry removes the entry label from the other entries that crossref it #7057 (comment) and When pasting an entry into jabref, check whether key already exists #8406)
2. try to merge these entries

I find that I cannot merge the entries with the contextual menu. I seem only to be able to merge entries with different keys.

Appendix

No response

[ThiloteE]

#8644 is a similar or close variant of this issue.

[HoussemNasri]

Refs #6190