QVBoxLayout closeLayout = new QVBoxLayout();
closeLayout.addWidget(new QLabel(tr("Closed Notebooks")));
closedBookList = new QListWidget();
closedBookList.setSortingEnabled(true);
closedBookList.setSelectionMode(QAbstractItemView.SelectionMode.MultiSelection);
closeLayout.addWidget(closedBookList);
openBookList.itemSelectionChanged.connect(this, "openBookSelected()");
closedBookList.itemSelectionChanged.connect(this, "closedBookSelected()");
leftButton.clicked.connect(this, "toOpenList()");
rightButton.clicked.connect(this, "toClosedList()");