Internet Explorer

InternetExplorerDriver has a lot of challenges; it attempts to work with multiple different versions of Internet Explorer and generally does a very good job. These capabilities are used to try and ensure that sessions are properly cleaned out when reloading the browser (IE8 is particularly bad at clearing its cache), and then trying to x some issues with hovering. If you have ever tested an application that needs you to hover over an element to trigger some sort of popup, you have probably seen the popup ickering a lot, and had intermittent failures when trying to interact with it. Setting ENABLE_PERSISTENT_HOVERING and requireWindowFocus should work around these issues.