This class is used to encapsulate a sub panel.

Autodesk.AutoCAD.Customization.ElementBase
    Autodesk.AutoCAD.Customization.VersionableElement
        Autodesk.AutoCAD.Customization.CustomizationElement
            Autodesk.AutoCAD.Customization.RibbonItem
            Autodesk.AutoCAD.Customization.ICustomizationContainer
                Autodesk.AutoCAD.Customization.AbstractRibbonSubPanel
                    Autodesk.AutoCAD.Customization.RibbonRowPanel

Public Class RibbonRowPanel
Inherits AbstractRibbonSubPanel

public class RibbonRowPanel : AbstractRibbonSubPanel;