Lables and marks is not visible at Slider when set styles -fx-show-tick-marks:true and -fx-show-tick-labels:true.
When set -fx-show-tick-labels:true - lables is visible.
When set -fx-show-tick-marks:true - marks is visible.


Sample code to reproduce:

@Override
    public void start(Stage primaryStage) {
        final Slider slider = SliderBuilder.create().min(0).max(100).value(20).focusTraversable(false).build();
        
        final ToggleButton btn1 = new ToggleButton();
        btn1.setText("'-fx-show-tick-marks'");
        btn1.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                System.out.println("Set -fx-show-tick-marks:" + !slider.showTickMarksProperty().get());
                slider.setStyle("-fx-show-tick-marks:" + !slider.showTickMarksProperty().get() + ";");
            }
        });
        final ToggleButton btn2 = new ToggleButton();
        btn2.setText("'-fx-show-tick-labels'");
        btn2.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
               System.out.println("Set -fx-show-tick-labels:" + !slider.showTickLabelsProperty().get());
               slider.setStyle("-fx-show-tick-labels:" + !slider.showTickLabelsProperty().get() + ";");
            }
        });
        VBox root = new VBox();
        root.setSpacing(10);
        root.getChildren().addAll(slider, btn1, btn2);
        
        Scene scene = new Scene(root, 300, 250);
        
        primaryStage.setTitle(VersionInfo.getRuntimeVersion());
        primaryStage.setScene(scene);
        primaryStage.show();
    }