JSObject.removeMember doesn't work.
Discovered with Presidio b41.

Please try the following application:

import com.sun.webpane.webkit.JSObject;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class Main extends Application {
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Application.launch(args);
    }

    @Override
    public void start(Stage stage) throws Exception {
        WebView wv = new WebView();
        WebEngine e = wv.getEngine();
        
        JSObject strO = (JSObject) e.executeScript("new String('test me')");
        strO.setMember("newmember", "I am new member, and I'm here");
        strO.removeMember("newmember");
        Object o = strO.getMember("newmember"); // Should be undefined!
        System.out.println(o);
                
        stage.setScene(new Scene(wv));
        stage.show();
    }
}