The public documentation of FXMLLoader (http://docs.oracle.com/javase/8/javafx/api/javafx/fxml/FXMLLoader.html) says that there is a symbol for FXML bidirectional expression binding, so people expect this to work. Actually, when using the symbols (namely #{..}"), what one gets is an exception, as this feature apparently is not "enabled". I suspect that "enabled" means "implemented" or "supported".

Hence, the documentation should not tell about the existence of bidirectional bindings in FXML expression strings.