Cost Code Selector on EPWeeklyCrewTimeEntry — Cannot Hide ALL RECORDS Tab via Code Behind

I am working on a customization for the Weekly Crew Time Entry screen (EP507020) and I am stuck. I am hoping someone has solved this before.

What I Am Trying to Do

I want to filter the Cost Code dropdown on the Weekly Crew Time Entry screen so it only shows cost codes that are:

• Budgeted under the selected Project on the row
• Budgeted under the selected Task on the row
• Belonging to Account Group where groupCD = "L"
   

What I Have Tried

Attempt 1 — CacheAttached with PXSelector

 

    public class LGroupCD : BqlString.Constant<LGroupCD>
    {
        public LGroupCD() : base("L") { }
    }

    public class EPWeeklyCrewTimeEntry_Extension : PXGraphExtension<PX.Objects.EP.EPWeeklyCrewTimeEntry>
    {
        #region Event Handlers

        [PXMergeAttributes(Method = MergeMethod.Merge)]
        [PXRemoveBaseAttribute(typeof(CostCodeAttribute))]
        [PXDBInt]
        [PXUIField(DisplayName = "Cost Code", FieldClass = CostCodeAttribute.COSTCODE)]
        [PXSelector(typeof(
            Search2<PMCostCode.costCodeID,
                InnerJoin<PMBudget,
                    On<PMBudget.costCodeID,
                    Equal<PMCostCode.costCodeID>>,
                InnerJoin<PMAccountGroup,
                    On<PMAccountGroup.groupID,
                    Equal<PMBudget.accountGroupID>>>>,
                Where<PMBudget.projectID,
                    Equal<Current<EPActivityApprove.projectID>>,
                    And<PMBudget.projectTaskID,
                    Equal<Current<EPActivityApprove.projectTaskID>>,
                    And<PMAccountGroup.groupCD,
                    Equal<LGroupCD>>>>>),
            SubstituteKey = typeof(PMCostCode.costCodeCD),
            DescriptionField = typeof(PMCostCode.description),
            Filterable = true)]
        protected void _(Events.CacheAttached<PMTimeActivity.costCodeID> e) { }

        #endregion
    }

Result — ALL RECORDS tab still shows.

 

Has anyone successfully hidden the ALL RECORDS tab on a Cost Code selector via C# code behind only — without modifying ASPX? If so what approach did you use?
 

I am on Acumatica 2025 version.

Any help is greatly appreciated. Thank you.