Support for WebBrowserBrush.
Currently, RadHtmlPlaceholder is an IFrame which is being rendered on top of the Silverlight plugin. Therefore, no mouse or keyboard events are being fired.
DECLINED: Duplicate with http://feedback.telerik.com/Project/143/Feedback/Details/114177-htmlplaceholder-support-for-webbrowserbrush
Make it easier to use the HtmlPlaceholder w/ scripts. Much like the WebBrowser control API.