A session opened from the sidebar could land above the bottom, or show a
frame sitting lower and then snap up. The viewport was pinned before the
content was final: the recap note renders once the session record arrives
and grew the footer under the pinned viewport, and on large sessions
subagent task cards grow when their child sessions load, moving everything
above the viewport.
- The recap note holds the timeline reveal until the session record is in
memory, so it is part of the first finished picture.
- The scroll hook holds the reveal until the viewport is pinned; the reveal
itself runs once the content height has held still for two frames, with
one exact pin against the final height (bounded at 300ms).
- Sitting on the end of a session that is not producing output is an
invariant: content growth re-pins from a MutationObserver in the same
frame the list writes its layout, so no frame paints with the end out of
view. Output growth keeps gliding through followEnd, which now glides only
while the session is working.
Switching sessions ran as one synchronous commit: sidebar highlight, URL,
a full timeline remount with markdown re-parse, and around nine requests,
so nothing changed on screen for 150-250ms after the click.
- ChatContainer swaps the timeline on a deferred copy of the selection, so
the active row, URL, and tab commit first and the timeline renders behind
them; selection policy keeps reading the live store value.
- The message fetch starts before the selection is published.
- Sidebar rows stop re-rendering on a project switch: directory-scoped sync
hooks read the runtime context and a subscribable current-directory source
instead of the directory-bearing context; the grouping builder reads git
branches through a ref and section caches key the branches they use;
descendant ids are keyed by content. Rows per switch went from 73 to 8.
- Markdown skips the async re-render when the settled cached blocks are
already painted, and mounts synchronously once its lazy module is loaded;
the module is preloaded at boot.
- A timeline reveal gate holds a freshly opened session at opacity 0 while
any provisional markdown paint catches up (250ms cap), then fades the whole
timeline in once, so text, tools, and recap appear together.
- Switch fan-out trimmed: knowledge summary deduped, MCP status refreshed only
when stale, non-repo directories cached by the git repo check, OpenChamber
defaults cached briefly, agent memory reused for the same project, goal
text cached, PWA manifest rebuilt after the switch settles.
- Header tabs snap into the active state and keep the title at the same
height in both states.
- Prefetch on row press; composer focus moved off the commit.
`bun run profile:switch` records ack/content latency, longest task, and
requests per switch, cold and warm, and compares runs against a baseline.
Measured warm switch: ack 228ms to about 40-60ms, content 228ms to about
100-120ms.
Bohdan Triapitsyn