View_CreateCell not fire for all columns

        public RadForm1()
        {
            InitializeComponent();

            this.radGridView1.CreateCell += radGridView1_CreateCell;
        }

        private void radGridView1_CreateCell(object sender, GridViewCreateCellEventArgs e)
        {
            if (e.CellType == typeof(GridFilterCellElement))
            {
                if (e.Column.GetType() != typeof(GridViewTextBoxColumn))
                {
                    e.CellElement = new CustomGridFilterCellElement(e.Column as GridViewDataColumn, e.Row);
                }
                else //default filter cell for the rest of the columns
                {
                    e.CellElement = new DefaultGridFilterCellElement(e.Column as GridViewDataColumn, e.Row);
                }
            }
        }

        private void RadForm1_Load(object sender, EventArgs e)
        {
            // TODO: This line of code loads data into the 'nwindDataSet.Products' table. You can move, or remove it, as needed.
            this.productsTableAdapter.Fill(this.nwindDataSet.Products);
            this.radGridView1.DataSource = this.productsBindingSource;
            this.radGridView1.BestFitColumns();
            this.radGridView1.EnableFiltering = true;
        }

        public class CustomGridFilterCellElement : GridFilterCellElement
        { 
            public CustomGridFilterCellElement(GridViewDataColumn column, GridRowElement row) : base(column, row)
            {
            }

            protected override Type ThemeEffectiveType     
            { 
                get    
                { 
                    return typeof(GridFilterCellElement);     
                }
            }

            protected override void CreateChildElements()
            {
                base.CreateChildElements();
                RadButtonElement btn = new RadButtonElement();
                btn.Text = "Click";
                this.Children.Add(btn);
            }

            public override bool IsCompatible(GridViewColumn data, object context)
            {
                //compatible with different than text columns
                return data.GetType() != typeof(GridViewTextBoxColumn);
            }
        }

        public class DefaultGridFilterCellElement : GridFilterCellElement
        { 
            public DefaultGridFilterCellElement(GridViewDataColumn column, GridRowElement row) : base(column, row)
            {
            }

            protected override Type ThemeEffectiveType     
            { 
                get    
                { 
                    return typeof(GridFilterCellElement);     
                }
            }

            public override bool IsCompatible(GridViewColumn data, object context)
            {
                //compatible with text columns
                return  data.GetType() == typeof(GridViewTextBoxColumn);
            }
        }