Is there an autocorrect feature in Expression Web 3 and if so how can I turn it off?

I have an aspx page that starts with the code

<%@ Page Title="" Language="C#" MasterPageFile开发者_StackOverflow="~/Views/

Every time I hit the save button, the text is changed to

<%@ Page Title="" Language="C#" MasterPageFile="Views/

(with the tilde and slash missing).

Why does Expression Web 3 do this and how can I turn this off?