GetSafeHtmlFragment adds a div tag after an input - Why?

Microsoft.Security.Application.Santizier.GetSafeHtmlFragment("<input type=""text"" />")

returns

<input type="text" /> <开发者_如何学C;div></div>

I assume this is some sort of security feature - why does it do this?

This is reported as a bug here: http://wpl.codeplex.com/workitem/15926