In page flow (200% zoom), the S11 follow logic re-pinned the document on
any scroll without wheel, touch, pointer or scroll-key input, so Tab,
Shift+Tab, focus(), find-style reveals and dialog return focus were pulled
back to the tail with focus thousands of pixels off screen.
Re-pin only a downward scroll with no reader input while following (scroll
anchoring as content grows). Count Tab as reader input, expire the reader
flag after two frames, and resume following when a transcript is opened.
jason.woltje
62ba124f2c