For the history feature to work in IE, the page must have an iFrame element with id '_historyFrame' pointed to a page that ...

For the history feature to work in IE, the page must have an iFrame element with id '__historyFrame' pointed to a page that gets its title from the 'title' query string parameter and calls Sys.Application._onIFrameLoad() on the parent window. This can be done by setting EnableHistory to true on ScriptManager.