though unspecified, I would expect the event to be fired only if there's a state transition from not-editing -> editing. TreeCell behaves as expected, List/TableCell don't

Failing test for ListCell:

    @Test
    public void testListEditStartOnCellTwiceStandalone() {
        ListView<String> control = new ListView<>(FXCollections
                .observableArrayList("Item1", "Item2", "Item3", "Item4"));
        control.setEditable(true);
        control.setCellFactory(TextFieldListCell.forListView());
        new StageLoader(control);
        int editIndex = 1;
        IndexedCell cell = getCell(control, editIndex);
        SimpleIntegerProperty counter = new SimpleIntegerProperty(0);
        control.addEventHandler(ListView.editStartEvent(), e -> counter.set(counter.get() + 1));
       
        // start edit on control
        cell.startEdit();
        // start again -> nothing changed, no event
        cell.startEdit();
        // test editEvent
        assertEquals("second start on editing cell must not fire event", 1, counter.get());
    }