Why is the window jerks while dragging?

The problem is that the window shakes when you drag and it deviates from the cursor. Why can it 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); //the stage.initStyle(StageStyle.UNDERDECORATED); //grab your root here root.setOnMousePressed(new EventHandler() { @Override public void handle(MouseEvent event) { xOffset = event.getSceneX(); yOffset = event.getSceneY(); } }); //move around here root.setOnMouseDragged(new EventHandler() { @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); } }