How do dual-engine browsers work? Do you manually switch between engines? Is there some sort of automatic "this page looks better in this engine" determination that happens?
There's probably a whitelist of sites that still require Trident. The reason for this is that there are a lot of Chinese websites that are still only IE6-compatible (this is a result of many Chinese installs of Windows being pirated copies of XP running IE6 - they don't want to upgrade to new versions of IE or Windows for fear of losing their OS validation). The Chinese internet is currently in a transitional period, with many established sites still working only with older versions of Trident, while newer sites (particularly mobile sites, and particuarly those targeted at the middle- and upper-class) support modern engines. Such dual-engine browsers help to ease that transition.
