a client's page that was built for ie7 was tagged using the compatibility mode meta tag, so that it rendered correctly on ie8 as well. this worked for a while. recently, testing the page reveals some severe issues, that are resolved only once the 'compatibility mode' button at the top of the browser is pressed. the tag is correct and is correctly positioned in the document, and the source code hasn't changed. what could have happened?
this is the code:
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />