On one of my sites, IE 8 is displaying the compatibility view button despite the presence of the X-UA-Compatible header. In IE 9, adding this header removes the button and sets the correct rendering mode, but why doesn't it do the same under IE 8? Apr 20, · Using IE9, click the only button on the screen to take you to the Test view. You'll notice nothing shows up in the console and the routing doesn't happen. The page content doesn't change and the URL doesn't update to show the new route. Aug 03, · When I debug it, I can set Document Mode to IE8 and it works, but in IE9 mode it doesn't. I use iframe in test code, because I use TinyMCE in my project (latest version TinyMCE has this problem). Should I modify something or this code can't work in IE9? I tried both IE9 32bit and IE9 64bit. Thank you. Valya.