Why is the window twitching when dragging?

Question

Java

The problem is that the window shakes while dragging and it deviates from the cursor. Why might this be?
Here is the code:

package youpackagename;

import java.awt.Color;
import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.fxml.FXMLLoader;
import javafx.geometry.Rectangle2D;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.input.MouseEvent;
import javafx.stage.Screen;
import javafx.stage.Stage;
import javafx.stage.StageStyle;

/**
 *
 * @author keeptoo
 */
public class JavaFXMovable extends Application {

   //define your offsets here
    private double xOffset = 0;
    private double yOffset = 0;
    
    @Override
    public void start(Stage stage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
        //you can use underdecorated or transparent.
        stage.initStyle(StageStyle.TRANSPARENT);
        //stage.initStyle(StageStyle.UNDERDECORATED);
       
       //grab your root here
             root.setOnMousePressed(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                xOffset = event.getSceneX();
                yOffset = event.getSceneY();
            }
        });
        
        //move around here
        root.setOnMouseDragged(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                stage.setX(event.getScreenX() - xOffset);
                stage.setY(event.getScreenY() - yOffset);
            }
        });
       
        Scene scene = new Scene(root);
        stage.setScene(scene);   

        stage.show();
    }

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

Answer 1

I'll duplicate the answer from the comments.
Try this: in the first handler:

xOffset = stage.getX() - event.getScreenX();
yOffset = stage.getY() - event.getScreenY();

And in setOnMouseDragged:

stage.setX(event.getScreenX() + xOffset);
stage.setY(event.getScreenY() + yOffset);