def flags(self, index):
        """"Determines interaction allowed with table cells.

        See :qtdoc:`QAbstractItemModel<QAbstractItemModel.flags>`, 
        and :qtdoc:`subclassing<qabstractitemmodel.subclassing>`
        """
        if index.column() == 0 or index.column == self.headers.index('Reps'):
            return QtCore.Qt.ItemIsEditable | QtCore.Qt.ItemIsEnabled | QtCore.Qt.ItemIsSelectable
        else:
            return QtCore.Qt.ItemIsEnabled