[DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Content)]
[JsonAttribute(false)]
[NotifyParentPropertyAttribute(true)]
[PersistenceModeAttribute(PersistenceMode.InnerProperty)]
public virtual TableItemStyle HeaderStyle { get; }

<DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Content)> _
<JsonAttribute(False)> _
<NotifyParentPropertyAttribute(True)> _
<PersistenceModeAttribute(PersistenceMode.InnerProperty)> _
Public Overridable ReadOnly Property HeaderStyle As TableItemStyle
	Get

This style is based on the grid's HeaderStyle property. If you are grouping on a single column, you probably won't have to change this style. If you are creating several levels of grouping, however, you will usually set the BackColor and ForeColor of each group header/footer to a different value to emphasize the structure of the data.