private void refreshView() {
        // We want to add in the 'All/none' DocumentType, at the top.
        List<DocumentType> selectableTypes = new ArrayList<>(visibleTypes);
        selectableTypes.add(0, SELECT_ALL_OR_NONE_DOCUMENT_TYPE);

        // To refresh the view we need to set the row data again.
        cellTable.setRowData(0, selectableTypes);
        cellTable.setRowCount(selectableTypes.size());
    }
@return A set of types to include, or empty if the type filter is not active
stroom-core-client/src/main/java/stroom/explorer/client/presenter/TypeFilterPresenter.java