Clicking the collapsed bar set expanded=true and started a smooth
scrollToBottom — but the scroll position was still legitimately inside
the collapse zone (that's why the bar was showing), so the hysteresis
listener re-collapsed the dock on the very next scroll event, then
re-opened it when the scroll arrived: open → snap shut → reopen.
The machine had no notion of intent. Now the bar click sets an
expandIntent flag that suppresses the collapse branch; it clears when
the scrollToBottom promise settles (completion or interruption) or after
a 2s safety net, so a user yanking the scroll away mid-reveal collapses
the dock again instead of wedging it open.
Verified live: click = exactly one transition (bar→open at ~26ms, stays
open, lands at d=1); collapse still healthy afterward; mid-reveal
interrupt re-collapses within ~300ms.
Amos
3c4eac8061