Custom Blocks Creating in C# with Editors WinForms Control

public class MyTokenizedTextBlockElement : TokenizedTextBlockElement
{
    private CheckBoxElement checkBox;

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

    protected override void CreateChildElements()
    {
        base.CreateChildElements();

        int index = this.Children.IndexOf(this.RemoveButton);
        this.checkBox = new CheckBoxElement();
        this.checkBox.StretchVertically = true;
        this.checkBox.StretchHorizontally = false;
        this.Children.Insert(index, this.checkBox);
    }
}

private void autoCompleteBox_CreateTextBlock(object sender, CreateTextBlockEventArgs e)
{
    if (e.TextBlock is TokenizedTextBlockElement)
    {
        e.TextBlock = new MyTokenizedTextBlockElement();
    }
}