FULL PRODUCT VERSION :
java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
macOS Sierra 10.12.5

A DESCRIPTION OF THE PROBLEM :
Violate the following guidelines.

"Position buttons as expected. Any buttons in the bottom right of a dialog should dismiss the dialog. An action button, which initiates the dialog’s primary action, should be farthest to the right. A Cancel button should be to the immediate left of the action button. If a third dismissal button exists, it should be to the left of the Cancel button."

* https://developer.apple.com/macos/human-interface-guidelines/windows-and-views/dialogs/

Although you may think that this problem is functionally acceptable,
On osx platform it seems to be a serious problem.
At the Mac App Store review, there is a potential risk that the application will be rejected.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Open Color Picker's custom color dialog

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Button order:

CANCEL, USE, SAVE(Default Button)
ACTUAL -
Button order:

SAVE(Default Button), USE, CANCEL



REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.ColorPicker;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class CustomColorTest extends Application{

@Override
public void start(Stage primaryStage) throws Exception {

ColorPicker colorPicker = new ColorPicker();
BorderPane root = new BorderPane(colorPicker);
root.setPadding(new Insets(16));
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.show();
}

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

---------- END SOURCE ----------