Called when the view item is changed by the user.
        
        :param      start | <QDate> || <QDateTime>
                    end   | <QDate> || <QDateTime>

def viewChanged(self, start, end):
        """
        Called when the view item is changed by the user.
        
        :param      start | <QDate> || <QDateTime>
                    end   | <QDate> || <QDateTime>
        """
        if type(start) == QDate:
            delta           = self._dateStart.daysTo(start)
            self._dateStart = start
            self._dateEnd   = end
            self.adjustChildren(delta)

        else:
            delta = self._dateStart.secsTo(start)
            self._dateStart = start.date()
            self._timeStart = start.time()
            
            self._dateEnd = end.date()
            self._timeEnd = end.time()
            
            self.adjustChildren(delta, secs=True)
        
        self.adjustRange()
        
        self.syncDependencies()
        self.syncTree()