ADDITIONAL SYSTEM INFORMATION :
Windows / Java 18

A DESCRIPTION OF THE PROBLEM :
In JavaFX 8 the scrollbar of a ListView could be "pinned/dragged" to the bottom of the ListView so when new items were put into the List it scrolls automatically to the lastindex position visible. Means autoscroll. I ported my application to JavaFX 20 and the behaviour changed - the scrollbar does not stick/pin anymore so a workaround would be to call scrollTo on every insert which results in poor performance. The call scrollTo was not needed in JavaFX 8 it provides best performance also on hundreds of thousands of inserts...


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
From a Task fill the List assigned to the Listview:
try (InputStreamReader reader = (new InputStreamReader(input))) {
LineIterator it = IOUtils.lineIterator(reader);
       while (it.hasNext()) {
        final String s = it.next();
        Platform.runLater(() -> {list.getItems().add(s););}
       }
Before drag the scrollbar to the bottom of the List

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Autoscroll will happen until you touch the scrollbar to othe direction
ACTUAL -
The List grows and the scrollbar raise/moves in upper direction as the List is beeing filled.

FREQUENCY : always