Open a window with a ListView, move the mouse over the ListView and scroll down. Nothing happens, because VirtualFlow computes the scrolling delta this way:
virtualDelta = event.getTextDeltaY() * lastCellLength;
but at this time lastCellLength is -1.
virtualDelta = event.getTextDeltaY() * lastCellLength;
but at this time lastCellLength is -1.