SMART datagrid v.1 > Classes > ColumnHeader
It specifies whether to display filter handle by HandleVisibility constant or undefined.
If specify undefined or a wrong value, it will follow the value set in OperateOptions.filterHandleVisibility.
Defaults to undefined.
var header = grid.focusedColumn().header();
header.setFilterHandleVisibility('always');
column.setHeader({
filterHandleVisibility: DataLudi.HandleVisibility.HIDDEN
});