JavaFX应用程序在关闭后仍然运行

关闭我的javaFX应用程序时遇到问题，当我点击我的舞台上的关闭按钮时，我的应用程序消失但是如果我在我的任务管理器中找到它，我的应用程序仍然没有关闭。
我试图使用下面的代码强制它关闭主线程和所有子线程，但问题仍然存在。

I'm having problem to close my javaFX application, when I click the close button from my stage, my application disappears but if I look for it in my task manager my application still there without close. I've tried to use this code below to force it close the main thread and all childrens threads but the problem persists.

primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() {

            @Override
            public void handle(WindowEvent t) {
                Platform.exit();
            }

        });