Hi Andy! In a previous mail, I observed that a method like `BehaviorBase.addHandlerLast` suggests to me that we're lacking core tools in the JavaFX framework. In this case, we want to ensure that an event handler is always invoked before (or after) other event handlers.
One way to do that might be to support prioritized event handlers at the core level, instead of creating new API that seems like a workaround. I've created a proof of concept for prioritized event handlers [0], which might be a moderate-effort but high-value addition to JavaFX. [0] https://github.com/openjdk/jfx/pull/1266
