rich-text-area VS RichTextFX

Gluon's RichTextArea is GPL 3 (not ideal for my project), bugs abound, and hasn't been touched in a year.

Actually, there is Have you ever wondered why JavaFX controls are made in Java code and not FXML, even custom ones (like this here from Gluon)

RichTextFX isn't great -- documentation is generally unhelpful and not much development lately. I've also found bugs in the component and figuring my way around internals is hard for a new-ish Kotlin dev.

RichTextFX is very much Some Assembly Required and there isn't much documentation. I would definitely say it's not easy to use IMHO. I'm currently working on creating a word processing control with it, but it's still very much a work in progress. If you go the route of using RichTextFX, the repo might help you figure some things out.

RichTextFX provides decent syntax highlighting for JavaFX. The project is barely active but works great nevertheless.

RichTextFX issue

This is a tough one. JavaFX doesn't currently have that capability. This would involve a lot of font metrics and line metrics calculations. The API currently does not have public methods for such. Might be added in future versions of javafx.

RichTextFX - This fits the bill. It uses following subcomponents..

VirtualizedFX and TextFlow will be key to creating stylized text editor if you decide to venture that direction. A game changer. RichtextFX is the most popular but uses Flowless as a virtualised container for TextFlow display, hence has many dependencies.