I had the same issue, I’m running it on Linux and looking at the Developer Tools console it said it could not find “./editorglue” and would fail to load the extension. “EditorGlue.js” indeed exists and I presume this works in Windows as it does not care about case, but in Linux it matters, to fix it: inside extension.js is I changed:
const editorglue_1 = require(“./editorglue”);
to
const editorglue_1 = require(“./EditorGlue”);

ps. This is a great extension by the way!

https://github.com/Phrogz/visual-scxml-editor/issues/45