[BLUEJ-1269] error-message on startup

After launching BlueJ, while the splash-page is still showing, a window comes up with an error ( screenshot at: https://imgur.com/5aT7XwJ )

BlueJ still finishes starting up and brings me to my most recent project (w/ the error-window still waiting for me to dismiss it).
After dismissing the error, everything still continues okay. (Hence the "low priority".)
This is on MacOS 10.14.3, BlueJ 4.2.1. ( bluej-debuglog.txt looks normal; it's below)
This happened with a fresh install of BlueJ.
It does not happen for a different user on my machine (!).
I deleted my old bluej.properties and actually the entire ~/Library/Preferences/org.bluej/ , but it still happened.
I'm not launching from a command-line where shell-environments might have some effect.
Afaict, there aren't any symlink dirs that I'm trying to use or pass through.
My bluej.properties is being correctly read and (on close) written back w/ updates.

Here's bluej-debuglog.txt:

BlueJ run started: Thu May 16 19:16:19 EDT 2019 BlueJ version 4.2.1 Java version 11.0.2 JavaFX version 11.0.2+1 Virtual machine: OpenJDK 64-Bit Server VM 11.0.2+9 (Oracle Corporation) Running on: Mac OS X 10.14.3 (x86_64) Java Home: /Applications/BlueJ 4.2.1/BlueJ.app/Contents/JDK/Home

Detected language "english" based on iso639-2 code "eng" Opening project: /Users/ibarland/Foof 1558048583131: Listening for JDWP connection on address: 127.0.0.1:50556 Connected to debug VM via dt_socket transport... Communication with debug VM fully established.

It's a bit puzzling to me -- I can't narrow down why it works for another user on my machine, but not for me!

Cheers, --Ian B.

Issue metadata

Issue type: Bug
Priority: Low