In this code example the content of ScrollPane disappears under certain situations.

If I set scrollPane.setVvalue(Double.MAX_VALUE), while the ScrollPane has no vertical scrollbar, strange behavior occurs: The content appears below the scroll pane.

What I actually wanted, is to scroll to the bottom (if there is no scroll bar, nothing should happen).

I seems, it only works after I resized the window vertically.

Run the code. Click scroll. Nothing happens (correct behavior). Enlarge the window vertically. Click scroll again. The content appears beneath the black Rectangle.



import javafx.application.Application;
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ScrollPane;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

public class TestApp3 extends Application {

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

    public void start(final Stage stage) throws Exception {

        final VBox root = new VBox();

        final ScrollPane scrollPane = new ScrollPane();

        final VBox vBox = new VBox();
        vBox.setAlignment(Pos.BOTTOM_CENTER);

        for (int i = 0; i < 5; i++) {
            vBox.getChildren().add(new Label("hallo"));
        }

        scrollPane.setContent(vBox);

        scrollPane.setHbarPolicy(ScrollPane.ScrollBarPolicy.NEVER);
        vBox.minHeightProperty().bind(scrollPane.heightProperty().subtract(2));
        vBox.minHeightProperty().addListener(new InvalidationListener() {
            @Override
            public void invalidated(Observable observable) {
                System.out.println(vBox.minHeightProperty().get());
            }
        });
        VBox.setVgrow(scrollPane, Priority.ALWAYS);
        Button button = new Button("scroll");
        button.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent actionEvent) {
                scrollPane.setVvalue(Double.MAX_VALUE);
            }
        });
        root.setAlignment(Pos.BOTTOM_RIGHT);
        root.getChildren().addAll(scrollPane, button, new Rectangle(50, 300));
        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.show();
    }
}