ListPage not filtering from DefaultValue of FilterBox field

When running a page built from the ListPage class, the list does not filter when you run the page when using DefaultValue set in a FilterBox screen field. Example, in the pers_status field of the FilterBox OnCreate is DefaultValue="Active"; The list shows all records when you come into the page. You then have to click the filter button to filter the page to Status=Active records.

CRM 7.3 SP2.1, CRM73 SDK.

Code for ListPage:

using System;
using System.Collections.Generic;
using System.Text;
using Sage.CRM.WebObject;
using Sage.CRM.Controls;

namespace CRM73
{
public class PersonList : ListPage
{
public PersonList()
: base("Person", "CustomPersonList", "PersonFilterBox")
{
FilterByField = "pers_companyid";
FilterByContextId = (int)Sage.KeyList.CompanyId;

}

public override void AddNewButton()
{
string sUrl=Url("1202");
AddUrlButton("New Person","NewIndividual.gif",sUrl);
AddHelpButton("/Main Menu/Default.htm#cshid=User/AI_AddingNewPersonToExis.htm");
}
}
}