Редактор winforms html

//CODE in C#
webBrowser1.Navigate("about:blank");
Application.DoEvents();
webBrowser1.Document.OpenNew(false).Write("
Edit this text
"); 

foreach (HtmlElement el in webBrowser1.Document.All)
{
    el.SetAttribute("unselectable", "on");
    el.SetAttribute("contenteditable", "false");
}

webBrowser1.Document.Body.SetAttribute("width", this.Width.ToString() + "px");    
webBrowser1.Document.Body.SetAttribute("height", "100%");     
webBrowser1.Document.Body.SetAttribute("contenteditable", "true");
webBrowser1.Document.DomDocument.GetType().GetProperty("designMode").SetValue(webBrowser1.Document.DomDocument, "On", null);
webBrowser1.IsWebBrowserContextMenuEnabled = false;
html5