Returns the list of columns that are specified based on the column
        view for this widget.
        
        :return     [<orb.Column>, ..]

def specifiedColumns(self):
        """
        Returns the list of columns that are specified based on the column
        view for this widget.
        
        :return     [<orb.Column>, ..]
        """
        columns = []
        table = self.tableType()
        tree = self.treePopupWidget()
        schema = table.schema()
        
        if self._specifiedColumns is not None:
            colnames = self._specifiedColumns
        else:
            colnames = tree.columns()
        
        for colname in colnames:
            if isinstance(colname, Column):
                columns.append(colname)
            else:
                col = schema.column(colname)
                if col and not col.isProxy():
                    columns.append(col)
        
        return columns