StyledTextArea scrolls to the caret every time span style is changed

I have a StyleClassedTextArea and load a String into it. I have a button event which calls setStyleClass a number of times using data external to the document. For some reason, when I call it, the text area always automatically scrolls to the bottom of the document. I have tried all kinds of variations, but it happens. Also, when I make the setStyleClass dependent on the document’s content changing and I edit the text in the middle of the text field, it scroll-jumps into a position where the line I am editing becomes the bottom-most line in the view. What am I doing wrong?

Thanks,

Matthias

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Minimal Code Example (just paste a lot of text into the field and click the button and provide some stylesheet in the css file defining a ‘red’ style):

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package application;

//imports ...

public class Main extends Application {

private Scene scene;
private StyleClassedTextArea textArea;

@Override
public void start(Stage stage) {

    stage.setTitle("ScrollTest);

    try {
        BorderPane root = new BorderPane();
        textArea = new StyleClassedTextArea();
        textArea.setWrapText(true);

        BorderPane border = new BorderPane();
        HBox topBox = new HBox();

        Button updateButton = new Button("foo");            
        updateButton.setPrefSize(100, 20);
        updateButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override public void handle(ActionEvent e) {
                textArea.setStyleClass(5, 10, "red");
            }
        });


        topBox.getChildren().addAll(updateButton);

        scene = new Scene(border, 600, 400);
        border.setCenter(textArea);

        border.setTop(topBox);
        scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());

        stage.setScene(scene);
        stage.show();

    } catch(Exception e) {
        e.printStackTrace();
    }
}

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

[mgrabmair]

@TomasMikula I am happy to see this is being picked up. My project ended up being abandoned, so I did not get back to this, but it is good to hear that this is a possibility. Thanks for the help!

[JordanMartinez]

It might be something else than Point2D, to account for the case when the caret is out of view (and in that case indicates whether it is before or after the currently displayed text). Also, it would be more like Bounds than Point2D anyway.

I forgot that sometimes the position of the anchor can change as well (is it in relation to the caret? Or the end of the selection?) Yeah, Bounds makes more sense.