I know that in Tridion 2013 there is a flag in the ambient data framework which informs the website application whenever session preview is requested. However, i would also like to know when the experience manager itself is open and the site runs in its iframe inside. I have considered doing some javascript coding (detect the iframe in javascript and act accordingly) but i would much rather do this server-side. I do know that, when an editor opens up the experience manager, the page is reloaded.
Anyone have any ideas, or know any headers being set when the experience manager is active?
Regards,
Rogier