SMART datagrid v.1 > Classes > GridHeader
Specify the distance between check box or image and text which is displayed in header cell.
If itemGap property of ColumnHeader is undefined, it will use this property.
Defaults to 2.
grid.setHeader({
itemGap: 4,
itemOffset: 2
});
// or, set individually.
grid.header().setItemGap(4);