One datagrid more checkbox columns

[frankgao]

There one datagrid, and two or more than two checkbox columns.
When I check the ck row,but the ck2 columns is checked at the same time. why?

Code:

columns: [[
                { field: 'sysfunid', hidden: true, title: 'ID' },
                { field: 'sysfunnumber', title: 'sysfunnumber', width: '120px', sortable: true },
                { field: 'ck', checkbox: true },
                { field: 'ck2', checkbox: true },
            ]],

[stworthy]

You can not define more than one check column on a datagrid.

[frankgao]

You can not define more than one check column on a datagrid.

If one datagrid need more then one column uses checkbox how can do it?
Is there have demo?