How to avoid displaying specific columns from displaying in the column chooser?

public class ColumnChooserPopupExt : Syncfusion.WinForms.DataGrid.Interactivity.ColumnChooserPopup
{
    private SfDataGrid DataGrid { get; set; }
    public ColumnChooserPopupExt(SfDataGrid sfDataGrid) : base(sfDataGrid)
    {
        this.Controls.Remove(this.ColumnChooser);
        DataGrid = sfDataGrid;
        ColumnChooser = new ColumnChooserExt(sfDataGrid);
 
        ////UnComment this if you want to close the popup when OK button is clicked
        //ColumnChooser.OKButton.Click += Close_ColumnChooserPopup;
 
        ColumnChooser.CancelButton.Click += Close_ColumnChooserPopup;
        ColumnChooser.BorderStyle = BorderStyle.None;
        ColumnChooser.ColumnChooserLabel.Visible = false;
        this.Controls.Add(ColumnChooser);
    }
 
    private void Close_ColumnChooserPopup(object sender, EventArgs e)
    {
        if (this.DataGrid.GetTopLevelParentDataGrid().FindForm() != null)
            this.DataGrid.GetTopLevelParentDataGrid().FindForm().Focus();
        this.Hide();
    }
}
 
public class ColumnChooserExt : Syncfusion.WinForms.DataGrid.Interactivity.ColumnChooser
{
    /// <summary>
    /// The grid attached with the column chooser.
    /// </summary>
    private SfDataGrid dataGrid;
 
    /// <summary>
    /// Initializes a new instance of the sfDataGrid
    /// </summary>
    /// <param name="sfDataGrid">The data grid which needs to be attached to the control.</param>
    public ColumnChooserExt(SfDataGrid sfDataGrid) : base(sfDataGrid)
    {
        dataGrid = sfDataGrid;
        dataGrid.Columns.CollectionChanged += Columns_CollectionChanged;
    }
 
    private void Columns_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        this.CheckedListBox.DataSource = dataGrid.Columns.Where(x => x.MappingName != "OrderID" && x.MappingName != "CustomerID");
    }
 
    protected override void AddCheckedListBox()
    {
        base.AddCheckedListBox();
 
        this.CheckedListBox.DataSource = dataGrid.Columns.Where(x => x.MappingName != "OrderID" && x.MappingName != "CustomerID");
    }
 
    protected override void OnSearchBoxTextChanged(object sender, EventArgs e)
    {
        base.OnSearchBoxTextChanged(sender, e);
 
        List<GridColumn> searchedItems = new List<GridColumn>();
        if (!string.IsNullOrEmpty(this.SearchTextBox.Text))
        {
            searchedItems.Clear();
            searchedItems = this.dataGrid.Columns.Where(item => (item.HeaderText.ToLower().Contains(this.SearchTextBox.Text.ToLower()) && item.MappingName != "OrderID" && item.MappingName != "CustomerID")).ToList();
            this.CheckedListBox.DataSource = null;
            this.CheckedListBox.DataSource = searchedItems;
        }
        else
            this.CheckedListBox.DataSource = dataGrid.Columns.Where(x => x.MappingName != "OrderID" && x.MappingName != "CustomerID");
 
        this.CheckedListBox.Invalidate();
 
    }
}