A little known feature of Internet Explorer 9 (IE9) is the ‘compatibility button’. The purpose of this button is to display correctly (as the designer intended) web-pages designed for earlier version of Internet Explorer.
The button will be found on the right of the address bar, and look like a piece of torn paper. when pressed, the icon changes from grey to a coloured one. The button can be toggled like an on/off switch.
When a webpage is compatible with Internet Explorer 9 the button is not displayed.