Weka 3.8.1/3.9.1 introduced a custom classloader mechanism for packages, which unfortunately has impacted how .props files are being loaded (or not loaded!). This only became apparent when running the graphviz-treevisualize plugin as package rather than from within my IDE.
Instead of just fixing that problem, I also made it a bit more flexible, i.e., you can now
- display the graph,
- save the dotty data or
- save the graph.
The new release is 2017.3.3