def _closeResources(self):
        """ Disconnects signals.
            Is called by self.finalize when the cti is deleted.
        """
        self.viewBox.sigRangeChangedManually.disconnect(self.setAutoRangeOff)
        self.viewBox.sigRangeChanged.disconnect(self.refreshMinMax)
Disconnects signals.
            Is called by self.finalize when the cti is deleted.