Another scenario (https://bugs.openjdk.org/browse/JDK-8364049 ) where the toolbar overflow button is erroneously displayed with fractional scale:

public class ToolbarBugApp extends Application {
    @Override
    public void start(Stage primaryStage) {
        ToolBar tb = new ToolBar(
                new Separator(Orientation.VERTICAL),
                new Button("Create Schema"));
        BorderPane bp = new BorderPane();
        bp.setTop(new HBox(tb));
        primaryStage.setScene(new Scene(bp, 600, 400));
        primaryStage.show();
    }