Processing Dialog box not appearing on Custom processing screen

Hello Community,

I am building a custom processing screen in Acumatica and facing an issue where the processing dialog (popup) is not showing when I click "Process" or "Process All."

Can someone help me figure out what I’m missing? Below is the code I am using.
 

public class BusinessAccountMaintTSExt : PXGraph<BusinessAccountMaintTSExt>
    {
        // Use PXFilter for ProcessFilter
       public PXFilter<ProcessFilter> Filter;



        public PXProcessingJoin<BAccount, LeftJoin<Customer, On<Customer.bAccountID, Equal<BAccount.bAccountID>>>,
                Where<Customer.bAccountID, IsNull,
                    And<BAccount.type, NotEqual<BAccountType.customerType>,
                    And<BAccount.type, NotEqual<BAccountType.vendorType>,
                    And<BAccount.type, NotEqual<BAccountType.employeeType>,
                    And<BAccount.type, NotEqual<BAccountType.combinedType>,
                    And<BAccount.type, NotEqual<BAccountType.branchType>,
                    And<BAccount.type, NotEqual<BAccountType.empCombinedType>>>>>>>>> ItemsProcessing;

   public BusinessAccountMaintTSExt()
        {


            ItemsProcessing.SetProcessDelegate(
        delegate (List<BAccount> list)
        {
            PXLongOperation.StartOperation(this, delegate
            {
                ProcessItems(list, Filter.Current);
            });
        });
}

public virtual void ProcessItems(List<BAccount> list, ProcessFilter filter)
        {
            if (list == null || list.Count == 0) return;

            if (filter == null || string.IsNullOrEmpty(filter.CustomerClassID))
            {
                // Acuminator disable once PX1050 HardcodedStringInLocalizationMethod [Justification]
                throw new PXException("Customer Class ID is required.");
            }

            // Process each selected item
            foreach (BAccount ba in list)
            {
                try
                {
                    ProcessSingleItem(ba, filter.CustomerClassID);
                    PXProcessing<BAccount>.SetProcessed();
                }
                catch (Exception ex)
                {
                    PXProcessing<BAccount>.SetError(ex.Message);
                    PXTrace.WriteError($"Error processing {ba.AcctCD}: {ex.Message}");
                }
            }
        }


public virtual void ProcessSingleItem(BAccount ba, string customerClassID)
        {
            BusinessAccountMaint graph = PXGraph.CreateInstance<BusinessAccountMaint>();
            graph.BAccount.Current = graph.BAccount.Search<BAccount.bAccountID>(ba.BAccountID);
            if (graph.BAccount.Current == null)
            {
                // Acuminator disable once PX1050 HardcodedStringInLocalizationMethod [Justification]
                throw new PXException("Business Account not found.");
            }


            if (graph.BAccount.Current.Type == BAccountType.CustomerType)
            {
                // Acuminator disable once PX1050 HardcodedStringInLocalizationMethod [Justification]
                throw new PXException("This Business Account is already a Customer.");
            }


            CustomerMaint customerGraph;
            try
            {
                // Get the ExtendToCustomer extension
                var ext = graph.GetExtension<BusinessAccountMaint.ExtendToCustomer>();
                if (ext == null)
                {
                    // Acuminator disable once PX1051 NonLocalizableString [Justification]
                    throw new PXException(PX.Objects.CR.MessagesNoPrefix.CannotConvertBusinessAccountToCustomer);
                }

                // Call the Extend method on the extension instance
                customerGraph = ext.Extend();

                if (customerGraph == null || customerGraph.BAccount.Current == null)
                {
                    // Acuminator disable once PX1051 NonLocalizableString [Justification]
                    throw new PXException(Messages.FailedToCreateCustomerGraph);
                }
            }
            catch (Exception ex)
            {
                // Acuminator disable once PX1051 NonLocalizableString [Justification]
                throw new PXException(Messages.FailedToCreateCustomerGraph, ex.Message);
            }
            // Set customer class ID
            customerGraph.BAccount.Current.CustomerClassID = customerClassID;

            // Handle class change
            customerGraph.BAccount.View.Answer = WebDialogResult.Yes;
            customerGraph.BAccount.UpdateCurrent();


            customerGraph.Actions.PressSave();

           // PXTrace.WriteInformation($"Successfully converted {ba.AcctCD} to customer");
        }

Any advice or example would be really appreciated!

Thank you in advance!