columnGroups property
Optional visual column groups rendered as an additional header row.
Column groups are layout-only metadata. Columns join a group through FdcGridColumn.groupId, which must match a unique FdcGridColumnGroup.id. Groups do not affect dataset schema, sorting, filtering, editing, or summary aggregation. Grouped columns are treated as normal scrollable columns; pin actions are hidden for them and programmatic pinning is ignored while the column belongs to a group.
Implementation
final List<FdcGridColumnGroup> columnGroups;