Checkboxes can be added in the grouping column by adding checkbox option in groupModel.
titleInFirstCol option is kept true, fixCols false and indent is used to indent the group titles.
Checked rows are obtained by call to getCheckedNodes() method of Group(). Title and summary rows are not included in the checked rows.
Checkboxes may also be bound to row selections similar to ordinary checkbox columns.
Ordinary checkbox columns can also be used together with cascade checkboxes e.g., OrderID column in this example.
Checkbox related options are present in groupModel
Checkbox related methods are present in Group
beforeCheck and check events are fired when checkboxes are checked/ unchecked.