When logged in to the CMS in edit mode, and using Internet Explorer (any version) the document mode seem to render as IE7 for Episervers framework, but it also affects the preview frame and thus the site I'm working on itself. It's a mobile-first responsive site and previewing it in edit mode causes it to render completely messed up.
I've tried setting the X-UA Compatible meta tag to Edge as both a meta tag hard coded in the masterpage and in Web.config as a CustomHeader. I've also tried injecting the tag from code-behind on page load but nothing seem to stop it from rendering as IE7 doc mode.
It works perfectly fine when viewing the site as a normal visitor outside of the CMS's edit mode.
The Epi-version we're using is: 6.1.379.502.
Any ideas on how to resolve this issue?
Not sure that it is possible but the site should be able to render ok. Developed other rwd websites and those worked ok. The CMS will render in something called quirksmode. There is also an upgrade for cms 6 r2 fixing some issues regarding the browser. I think it is included in the installation package if you download and install a new one.
Since you are using mobile firs approach and IE8/7 does not support media queries this is the problem. If you had have an responsive website but with desktop first it would probably have worked ok sadly.
This thread might help you as well: http://world.episerver.com/Modules/Forum/Pages/Thread.aspx?id=54436