I've made this a REALLY long time ago, there are better alternatives for designing diagrams for behavior trees or any other diagram. I personally use https://app.diagrams.net/ for designing diagrams especially for behavior trees and not my own app.
It's also free, available as a website or even as a standalone application on Windows, and I think it also supports linux, and it's also a LOT better than my app.
If you really want my app for Linux and the previous link won't suffice, I think I could make a Linux build, but I'm not 100% sure how well it will work.
