Base Method in a PXAction override delegate is null

I’m overriding the Print Shipment Confirmation menu option on the Shipments screen

In my code, I want the option to use my override, or use the base method.

When I call the BaseMethod from my delegate, it is null.  I’m not sure what to do.

Here is the code for my override:

        [PXOverride]
        public delegate IEnumerable PrintShipmentConfirmationDelegate(PXAdapter adapter);
        [PXButton]
        [PXUIField(DisplayName = "Shipment Confirmation")]
        public IEnumerable PrintShipmentConfirmation(PXAdapter adapter, PrintShipmentConfirmationDelegate BaseMethod)
        {
            try
            {
                SOShipment shipment = Base.Document.Current;

                string screenID = "SO302000";
                string reportID = "SO642000";
                string printerName;

                ICSPrintHubActions iCSPrintHubActions = SelectFrom<ICSPrintHubActions>
                                                        .Where<ICSPrintHubActions.screenID.IsEqual<@P.AsString>
                                                            .And<ICSPrintHubActions.reportID.IsEqual<@P.AsString>>>.View.Select(Base, screenID, reportID);
                if (iCSPrintHubActions == null)
                {
                    throw new PXException(ICSMessages.PrintHubActionNotFound, screenID, reportID);
                }

                if (iCSPrintHubActions.Active == false)
                {
                    if (BaseMethod != null)
                    {
                        return BaseMethod.Invoke(adapter);
                    }
                    else
                    {
                        return adapter.Get();
                    }
                }

----the rest of the code is not needed to show here...

The idea is that if the iCSPrintHubAction is not active, fire the BaseMethod.Invoke(adapter);

At least that is what I think I need to do.

Note that if I get rid of the BaseMethod.Invoke stuff, the override does what I want.  I’m just trying to do the non-overridden action if the test record is not active.

Any ideas why my BaseMethod from the Delegate is null?