Turn off IE Compatibility mode in MS Dynamics CRM 2011 or why indexOf doesn't work.

We'd been having navigation issues in MS Dynamics CRM 2011 for a while: Mouse scrolling wouldn't work and double clicking was necessary to select anything from a drop down menu. The issue would disappear if IE was using IE 9 document standards. The problem was that IE would "downgrade" itself to IE 7.

Somewhat bizarrely this wasn't occurring everywhere, it was just occurring in one of our environments causing loads of headaches for everybody. The testers were annoyed that they had, effectively limited functionality and kept forgetting to set document standards to IE 9 via developer tools. We weren't sure why this was happening in only one environment.

Things came to a head last week when I used a variation of my function getAllUserRoles and due to indexOf only being supported on IE > 9, it was working everywhere apart from on this environment. 

It turns out that there is a setting, introduced in UR12, called Load Pages in the most recent version of Internet Explorer, which modifies the headers so that the pages are rendered in the most recent version of IE.

Navigate to Settings -> Administration -> System Settings -> Customization.

Ticking this setting, will ensure that the default doc standards will be used and the heat death of the universe will have been staved off for another tick or two.