Blurry text appearance after some JavaFX TextArea manipulations - javafx

Question

I see a strange appearance of the text contained in a TextArea aftrer doing some changes of TextArea content and style.
With the simplified code shown below I reproducibly see this when I click the button 4 times:
But this is what I expected to see:
Note: If I then click into the TextArea I see the expected result.
What can can be done to get the expected result?
Note that I need to set textarea min/max width and height to get a nice appearance of the content.
Of course I could set it to a bigger value, but that would destroy the look that is required.
I tried setCache as proposed here but that did not work.
I have JavaFX-8 on Windows 8.1. I would also be interested what results are seen in newer versions.
EDIT
With JavaFX-13 the result is:
The text seems to be moved to the right instead of centered as specified in the css (and also to the bottom). I had ecpected that the text is postioned the same as on initial start of the application.
CSS:
.text-area-centered *.text {
-fx-text-alignment: center ;
}
.text-area-centered .scroll-pane {
-fx-hbar-policy: NEVER;
-fx-vbar-policy: NEVER;
}
Java:
public class Main extends Application {
private static final BackgroundFill blackBGF = new BackgroundFill(Color.BLACK, CornerRadii.EMPTY, Insets.EMPTY);
private static final BackgroundFill whiteBGF = new BackgroundFill(Color.WHITE, CornerRadii.EMPTY, Insets.EMPTY);
private static double textareaXY = 50;
private TextArea textarea = new TextArea();
private int clickNo = 1;
#Override
public void start(Stage primaryStage) {
BorderPane root = new BorderPane();
Scene scene = new Scene(root,400,400);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
VBox vb = new VBox();
root.setCenter(vb);
Button b = new Button("ClickMe");
b.addEventHandler(ActionEvent.ACTION, this::OnClickButton);
vb.getChildren().add(b);
vb.getChildren().add(textarea);
textarea.setEditable(false);
textarea.getStyleClass().add("text-area-centered");
textarea.setBackground(new Background(blackBGF));
textarea.setMinHeight(textareaXY);
textarea.setMaxHeight(textareaXY);
textarea.setMinWidth(textareaXY);
textarea.setMaxWidth(textareaXY);
textarea.setFont(new Font("Courier New",10));
textarea.setText("1 2 3\n4 5 6\n7 8 9");
primaryStage.show();
}
private void OnClickButton(ActionEvent event)
{
if(clickNo == 1)
{
textarea.setText("7");
textarea.setFont(new Font("Courier New Bold",24));
}
else if(clickNo == 2)
{
Region region = ( Region ) textarea.lookup( ".content" );
region.setBackground(new Background(blackBGF));
textarea.setStyle("-fx-text-inner-color: white;");
}
else if(clickNo == 3)
{
Region region = ( Region ) textarea.lookup( ".content" );
region.setBackground(new Background(whiteBGF));
textarea.setStyle("-fx-text-inner-color: black;");
}
else if(clickNo == 4)
{
textarea.setText("1 2 3\n4 5 6\n7 8 9");
textarea.setFont(new Font("Courier New",10));
}
clickNo++;
}
public static void main(String[] args) {
launch(args);
}
}