When typing in the WebView text areas of a "pure" JavaFX application, carriage returns result in line breaks in the text area:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class PureJFX extends Application {
    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage stage) throws Exception {
        WebView webView = new WebView();
        WebEngine webEngine = webView.getEngine();
        webEngine.loadContent("<textarea rows='5' cols='25'></textarea>");
        stage.setScene(new Scene(webView));
        stage.show();
    }
}

However, when the WebView is used in a mixed Swing and JavaFX application, using the JFXPanel, carriage returns are ignored:

import javax.swing.JFrame;
import javax.swing.SwingUtilities;

import javafx.application.Platform;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Scene;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class SwingJFX {
    public static void main(String[] args) {
        new SwingJFX();
    }

    public SwingJFX() {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.setSize(640, 480);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                final JFXPanel panel = new JFXPanel();
                frame.getContentPane().add(panel);
                frame.setVisible(true);

                Platform.runLater(new Runnable() {
                    @Override
                    public void run() {
                        WebView webView = new WebView();
                        WebEngine webEngine = webView.getEngine();
                        webEngine.loadContent("<textarea rows='5' cols='25'></textarea>");
                        panel.setScene(new Scene(webView));
                    }
                });
            }
        });
    }
}