if (e.getKeyCode() == KeyEvent.VK_DOWN) {
History refNext = model.getHistory().from(ref);
History curNext = model.getHistory().from(cur);
if (refNext.getNumVersions() > 1 && curNext.getNumVersions() > 1) {
model.setReferencePointInTime(refNext.sortAscending().get(1));
model.setCurrentPointInTime(curNext.sortAscending().get(1));
}
} else if (e.getKeyCode() == KeyEvent.VK_UP) {
History refNext = model.getHistory().until(ref);
History curNext = model.getHistory().until(cur);
if (refNext.getNumVersions() > 1 && curNext.getNumVersions() > 1) {