DataGrid Group Collapse/Expand Option

It would be really helpful if RadzenDataGrid has an option to set grouped row expand/collapse status after grouping instead of expanding all by default as it does currently, especially for datagrids with large amount of data per page.

There is a way to collapse group using GroupRowRender event:

Thanks for your suggestion, however since we display the entire grid first and allow users to group columns later, args.FirstRender is always false in the GroupRowRender event call back, which renders the solution non-applicable to our use case.

Note in the demo that nothing is logged when you expand the collapsed row.

The GroupRowExpand/GroupRowCollapsed callbacks are never fired from RadzenDataGrid.ExpandGroupItem.
Setting args.Expanded in OnGroupRowRendered gets passed onto ExpandGroupItem's expandedOnLoad which must be null to invoke the callbacks.