JabRef--master--latest.jar (https://builds.jabref.org/master/) as well as version 4.3.1-2 form Arch AUR (https://aur.archlinux.org/packages/jabref/)

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

Right clicking on any entry in any database and selecting "Open folder" results in the NullPointer exception below. The setup experiencing this problem is Arch Linux with i3 window manager and without desktop environment. Hence it could be that there is a dependency to some external SW that is not satisfied. This problem exists over multiple version already (~1y) over different Arch machines I operate. My guess is that there is some unknown dependency that I lack on my systems, which causes "open folder" to silently crash. I would be interested in tracking down what exactly is causing that issue. Might be something very obvious to you guys.

Steps to reproduce the behavior:

1. On Arch Linux + Jabref master latest or Jabref 4.3.1-2 from AUR: open any database where files have associated pdfs in their entires.
2. Right click, "open folder" --> exception below

10:51:41.270 [JabRef CachedThreadPool] ERROR org.jabref.FallbackExceptionHandler - Uncaught exception occurred in Thread[JabRef CachedThreadPool,5,main]
java.lang.NullPointerException: null
  at org.jabref.gui.desktop.os.Linux.openFolderAndSelectFile(Linux.java:54) ~[JabRef--master--latest.jar:?]
  at org.jabref.gui.desktop.JabRefDesktop.openFolderAndSelectFile(JabRefDesktop.java:171) ~[JabRef--master--latest.jar:?]
  at org.jabref.gui.BasePanel.lambda$null$49(BasePanel.java:348) ~[JabRef--master--latest.jar:?]
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[?:1.8.0_201]
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[?:1.8.0_201]
  at java.lang.Thread.run(Thread.java:748) [?:1.8.0_201]

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)

I'm happy to provide further details!