I confirm that flickering during scrolling it is in ST 2.1. Even on all types of iOS devices and it's noticable and annoying!!! It worked great there, much smoothly in ST 2.0.1 but now it looks almost similar like on Android devices (i mean looks similar badly). I can't explain why but it looks like they calculate scroller height and offsets everytime (even not in list). Who are interested in, just compare scrolling in Kitchen Sink in 2.1 and 2.0.1 (on iOS device, for instance, or in desktop Chrome with User Agent of iPhone or iPad). As for me, difference is obvious.
But if somebody knows secrets how to improve this perfomance or to make it similar to ST 2.0.1, please, share them (may be some tricks with css I missed or something else).
P.S.: And don't tell me to downgrade the app to 2.0.1. :) Too late, unfortunately.

