Hi,

JabRef version 4.2
MacOS High Sierra
Java 1.8.0_112 (also tested on 10.0.1)

Steps to reproduce:

1. Launch JabRef and TeXstudio
2. Select a bibliographic item
3. Click push to TeXstudio
4. Nothing happens

In settings 'External Programs' path to TeXstudio: /Applications/texstudio.app/Contents/MacOS/texstudio

Previously worked very well until latest upgrade JabRef to 4.2.

Thanks in advance,