JabRef version 5.0-dev (master--latest)

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

The possibility to mark entries seems to be gone. Was this removed for 5.0 on purpose, or is it not implemented yet? Sorry if I overlooked information that would point this out somewhere.

As usual, my system setup: Arch Linux, i3 window manager, java version:

java -version
java version "1.8.0_201"
Java(TM) SE Runtime Environment (build 1.8.0_201-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.201-b09, mixed mode)

Steps to reproduce the behavior:

1. Way 1: right click on any entry in the database: the context menu does not show any possibility to mark references.
2. Way 2: mark any reference in the database: the top menu does not provide any way for marking/unmarking an entry either.