Pop up in Modern UI

Hi everyone, I have an issue with creating a popup panel in Modern UI.
Below I have attached everything related to this popup.

        public PXSelect<BZSPFilter> BZSalespersonsDialog;

        #endregion

        #region Buttons

        #region BZViewSalespersons
        public PXAction<Table> BZViewSalespersons;
        [PXButton(CommitChanges = true, DisplayOnMainToolbar = false)]
        [PXUIField(DisplayName = "Salespersons", Enabled = true)]
        public void bZViewSalespersons()
        {
            if (Base.Views[CurrentViewName()].Cache.Current != null)
            {
                Base.Views[CurrentViewName()].RequestRefresh();
                BZSalespersonsDialog.View.AskExt(true);
            }
        }
        #endregion

        #region UsrBZSalesperson1
        public abstract class usrBZSalesperson1 : BqlInt.Field<usrBZSalesperson1> { }
        [SalesPerson]
        [PXUIField(DisplayName = BZFieldNames.SP1)]
        [PXFormula(typeof(Default<ARInvoice.customerID>))]
        [PXDefault(typeof(Search<CustSalesPeople.salesPersonID, Where<CustSalesPeople.bAccountID, Equal<Current<ARInvoice.customerID>>, And<CustSalesPeople.isDefault, Equal<True>>>>), PersistingCheck = PXPersistingCheck.Nothing)]
        public int? UsrBZSalesperson1 { get; set; }
        #endregion

        #region UsrBZSP1CommissionPct
        public abstract class usrBZSP1CommissionPct : BqlDecimal.Field<usrBZSP1CommissionPct> { }
        [PXDBDecimal(2)]
        [PXUIField(DisplayName = "Commission %", Enabled = false, Visible = false)]
        [PXFormula(typeof(Default<ARInvoice.customerID>))]
        [PXDefault(typeof(Search<CustSalesPeople.commisionPct, Where<CustSalesPeople.bAccountID, Equal<Current<ARInvoice.customerID>>, And<CustSalesPeople.isDefault, Equal<True>>>>), PersistingCheck = PXPersistingCheck.Nothing)]
        public decimal? UsrBZSP1CommissionPct { get; set; }
        #endregion

        #region UsrBZSalesperson2
        public abstract class usrBZSalesperson2 : BqlInt.Field<usrBZSalesperson2> { }
        [SalesPerson]
        [PXUIField(DisplayName = BZFieldNames.SP2)]
        [PXFormula(typeof(Default<ARInvoice.customerID>))]
        public int? UsrBZSalesperson2 { get; set; }
        #endregion

        #region UsrBZSP2CommissionPct
        public abstract class usrBZSP2CommissionPct : BqlDecimal.Field<usrBZSP2CommissionPct> { }
        [PXDBDecimal(2)]
        [PXUIField(DisplayName = "Commission %", Enabled = false, Visible = false)]
        [PXFormula(typeof(Default<ARInvoice.customerID>))]
        public decimal? UsrBZSP2CommissionPct { get; set; }
        #endregion

        #region UsrBZSalesperson3
        public abstract class usrBZSalesperson3 : BqlInt.Field<usrBZSalesperson3> { }
        [SalesPerson]
        [PXUIField(DisplayName = BZFieldNames.SP3, Visible = false)]
        [PXFormula(typeof(Default<ARInvoice.customerID>))]
        public int? UsrBZSalesperson3 { get; set; }
        #endregion

        #region UsrBZSP3CommissionPct
        public abstract class usrBZSP3CommissionPct : BqlDecimal.Field<usrBZSP3CommissionPct> { }
        [PXDBDecimal(2)]
        [PXUIField(DisplayName = "Commission %", Visible = false)]
        [PXFormula(typeof(Default<ARInvoice.customerID>))]
        public decimal? UsrBZSP3CommissionPct { get; set; }
        #endregion

  <px:PXSmartPanel runat="server" ID="BZSalespersonsCst" CaptionVisible="True" Caption="Salespersons" Key="BZSalespersonsDialog" LoadOnDemand="True" AutoReload="True" AutoRepaint="True">
    <px:PXLayoutRule runat="server" ID="CstPXLayoutRule2" StartRow="True" />
    <px:PXFormView runat="server" ID="CstFormView3" DataMember="CurrentDocument">
      <Template>
        <px:PXLayoutRule runat="server" ID="CstPXLayoutRule5" Merge="True" />
        <px:PXSegmentMask runat="server" ID="CstPXSegmentMask9" DataField="UsrBZSalesperson1" CommitChanges="True" AutoRefresh="True" />
        <px:PXNumberEdit runat="server" ID="CstPXNumberEdit10" DataField="UsrBZSP1CommissionPct" />
        <px:PXLayoutRule runat="server" ID="CstPXLayoutRule7" Merge="True" />
        <px:PXSegmentMask runat="server" ID="CstPXSegmentMask11" DataField="UsrBZSalesperson2" CommitChanges="True" AutoRefresh="True" />
        <px:PXNumberEdit runat="server" ID="CstPXNumberEdit12" DataField="UsrBZSP2CommissionPct" />
        <px:PXLayoutRule runat="server" ID="CstPXLayoutRule8" Merge="True" />
        <px:PXSegmentMask runat="server" ID="CstPXSegmentMask13" DataField="UsrBZSalesperson3" CommitChanges="True" AutoRefresh="True" />
        <px:PXNumberEdit runat="server" ID="CstPXNumberEdit14" DataField="UsrBZSP3CommissionPct" /></Template></px:PXFormView>
    <px:PXLayoutRule runat="server" ID="CstPXLayoutRule4" StartRow="True" />
    <px:PXPanel runat="server" ID="CstPanel6" SkinID="Buttons">
      <px:PXButton runat="server" ID="CstButton15" Text="OK" DialogResult="OK" /></px:PXPanel></px:PXSmartPanel>