def on_prefs ( self ):
        """ Handles the user requesting to set the user preference items for the
            table.
        """
        columns = self.columns[:]
        columns.extend( [ c
            for c in (self.factory.columns + self.factory.other_columns)
            if columns not in c ] )
        self.edit_traits(
            parent = self.control,
            view   = View( [ Item( 'columns',
                                resizable = True,
                                editor    = SetEditor( values       = columns,
                                                       ordered      = True,
                                                       can_move_all = False ) ),
                             '|<>' ],
                         title     = 'Select and Order Columns',
                         width     = 0.3,
                         height    = 0.3,
                         resizable = True,
                         buttons   = [ 'Undo', 'OK', 'Cancel' ],
                         kind      = 'livemodal' ) )

    #---------------------------------------------------------------------------
    #  Prepares to have a context menu action called:
    #---------------------------------------------------------------------------
dataset/ETHPy150Open enthought/traitsui/traitsui/wx/table_editor.py/TableEditor.on_prefs/swapped operands of `not in`