private void dragOverEvent(DragEvent event, N item, TreeTableRow<N> treeTableRow, TreeTableCell<N, N> treeTableCell) { if (item instanceof Folder && isMovable(item, treeTableRow.getTreeItem())) { int count = 0; treeItemChildrenSize(treeTableRow.getTreeItem(), count); setDragOverStyle(treeTableCell); event.acceptTransferModes(TransferMode.ANY); event.consume(); } }