This is preview!
The default page transition is now be a super fast and smooth fade out/in animation. All the 1.1 page transitions (slide, flip, etc.) have been tweaked to have a place in the animation where we fade out to accomodate the scroll jump, but we think this looks pretty sharp and always in control.
During a CSS-based page transition, jQuery Mobile will place the class name of the transition on both the "from" and "to" pages involved in the transition. It then places an "out" class on the "from" page, and "in" class on the "to" page. The presence of these classes on the "from" and "to" page elements then triggers the animation CSS rules defined above. As of jQuery Mobile version 1.1, animation class additions are queued, rather than simultaneous, producing an out-then-in sequence, which is friendlier for mobile rendering than our previous simultaneous transition sequence.