Yes, I can write the code for a simple JavaFX application that opens a window with a button labeled, "Hello, World!" using Markdown.

Here's an example of the code:

```
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class HelloWorld extends Application {

  @Override
  public void start(Stage primaryStage) {
    Button btn = new Button();
    btn.setText("Hello, World!");
    btn.setOnAction(event -> System.out.println("Hello, World!"));

    StackPane root = new StackPane();
    root.getChildren().add(btn);

    Scene scene = new Scene(root, 300, 250);

    primaryStage.setTitle("Hello, World!");
    primaryStage.setScene(scene);
    primaryStage.show();
  }

  public static void main(String[] args) {
    launch(args);
  }
}
```

This code creates a JavaFX application that opens a window with a button labeled, "Hello, World!". When the button is clicked, it will print "Hello, World!" to the console.
spam fails_task lang_mismatch pii not_appropriate hate_speech sexual_content quality toxicity humor helpfulness creativity violence