Adding a filed to that filters on the grid on a Maintanance form

Good day all,

I have added a project column to the grid on the reconciliation tab of the Fixed Assets form. After that I added a project ID on the header as shown below

When I select a project ID at the top I want it to filter the data below using the project ID selected. I have extended the AssetMant graph using the code below but when I publish I get errors

namespace PX.Objects.FA
{
  public class AssetMaint_Extension : PXGraphExtension<PX.Objects.FA.AssetMaint>
  {
    #region Event Handlers
     public PXFilter<GLTranFilter> Filter;

    protected virtual IEnumerable DsplAdditions()
    {
        if (Filter.Current != null && !string.IsNullOrEmpty(Filter.Current.UsrProjectFilter))
        {
            // Apply filter to the grid's data view based on UsrProjectFilter
            return DsplAdditions.Select().RowCast<FAAccrualTran>().Where(record =>
                record.usrPJ == Filter.Current.UsrProjectFilter);
        }
        else
        {
            // If UsrProjectFilter is not specified, return all records
            return DsplAdditions.Select();
        }
    }
    #endregion
  }
}

Here is the error I am getting.

I have also attached the customization package below.

What could be the issue?