Records the user minimum size for a column.
        
        :param      section | <int>
                    oldSize | <int>
                    newSize | <int>

def __setUserMinimumSize( self, section, oldSize, newSize ):
        """
        Records the user minimum size for a column.
        
        :param      section | <int>
                    oldSize | <int>
                    newSize | <int>
        """
        if self.isVisible():
            self._columnMinimums[section] = newSize