JavaFX: Why does stage.setResizable(false) cause additional margins?

Question

This small JavaFX test application

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.sce         


        

Answer 1

Although this is not explanation, it solves the problem:

@Override
public void start(final Stage primaryStage) throws Exception {
    final Dimension d = new Dimension(210, 110);
    final Rectangle rectangle = new Rectangle(d.width, d.height, Color.POWDERBLUE);
    final BorderPane pane = new BorderPane(rectangle);
    pane.maxWidth(d.height);
    pane.maxWidth(d.width);
    final Scene scene = new Scene(pane, d.width, d.height);
    primaryStage.setScene(scene);
    primaryStage.setResizable(false);
    primaryStage.setWidth(d.width);
    primaryStage.setHeight(d.height);
    primaryStage.show();
}

Key is setting width and height of the Stage at the right time.