A while back I developed a desktop-based text editor (Scrivenvar) that uses the Chain-of-Responsibility design pattern to help me author fairly involved text documents. The editor's high-level architecture resembles the following diagram:
Am I reinventing the wheel here? Are there any modern, cross-platform, liberal open-source (LGPL, MIT, Apache 2), text editor frameworks (such as xi or Visual Studio Code), that would enable (re)development of such a tool?
Scrivenvar is written in Java, but to my chagrin, Java 9+ no longer bundles JavaFX. The text editor was based on MarkdownWriterFX, itself based on JavaFX. This means there's no easy upgrade path, so I'm looking to rebuild the editor either as a cross-platform desktop application or as a web application.