ADDITIONAL SYSTEM INFORMATION :
OpenJFX 15.0.1

A DESCRIPTION OF THE PROBLEM :
When changing the ObservableList items in a ListView it always triggers selection changes, even if neither the order nor the items, but only properties of the single objects, change. These selection changes include a null selection followed by a reselection of the original selection.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a ListView with an ObservableList that includes an Extractor that propagates object's property changes. Change a property of an object that is part of the ObservableList. Observe the selection changes, even though the items of the ObservableList are still the same.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Selections should only change when the ObservableList items that affect the selections change.
ACTUAL -
Every ObservableList change triggers a null selection and a reselection afterwards

---------- BEGIN SOURCE ----------
The problem is this code in ListView.java (lines 1495 following). Especially content of old an new lists are not compared and the default selection is always updated.

private void updateItemsObserver(ObservableList<T> oldList, ObservableList<T> newList) {
            // update listeners
            if (oldList != null) {
                oldList.removeListener(weakItemsContentObserver);
            }
            if (newList != null) {
                newList.addListener(weakItemsContentObserver);
            }

            updateItemCount();
            updateDefaultSelection();
        }

        private void updateDefaultSelection() {
            // when the items list totally changes, we should clear out
            // the selection and focus
            int newSelectionIndex = -1;
            int newFocusIndex = -1;
            if (listView.getItems() != null) {
                T selectedItem = getSelectedItem();
                if (selectedItem != null) {
                    newSelectionIndex = listView.getItems().indexOf(selectedItem);
                    newFocusIndex = newSelectionIndex;
                }

                // we put focus onto the first item, if there is at least
                // one item in the list
                if (listView.selectFirstRowByDefault && newFocusIndex == -1) {
                    newFocusIndex = listView.getItems().size() > 0 ? 0 : -1;
                }
            }

            clearSelection();
            select(newSelectionIndex);
// focus(newFocusIndex);
        }
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Ignore null changes in selection listeners, but this makes certain programms impossible.

FREQUENCY : always