Isolated Session View (experimental)

What it is

What it is: an opt-in performance mode that renders the active session's chat in its own background renderer process, embedded invisibly inside the main window. The app looks and behaves exactly the same — same sidebar, same panel area, same composer — but the conversation you're looking at no longer shares a rendering thread with the rest of the app, so switching into it and typing in it stay fast even while Omniscio is grinding through dozens of other sessions' updates. There is always exactly one window and at most one extra process — sessions are swapped into the single embedded view in place, never one process per session.

Where: Settings → Performance → "Isolated session view (experimental)". Default OFF. Takes effect on the next session you click. Desktop only (mobile layout always uses the normal inline panel).

Why it exists (measured)

On a heavily loaded shell thread (load injector calibrated to real traces), the end-to-end click → session content painted time, 40 switches per arm:

	typical (p50)	slow-case (p90)	worst
Normal panel, under load	222ms	413ms	825ms
Isolated view, under load	34ms	75ms	99ms

Typing latency inside the isolated view stays ~2–3ms per keystroke regardless of shell load. The measurement harness is tests/perf/session-switch-isolation-ab.spec.ts (GO/NO-GO bar in tests/perf/isolation-ab-logic.ts); the mechanism E2E is tests/e2e/ui/isolated-session-view-spike.spec.ts.

Where to find it

Settings → Performance → "Isolated session view (experimental)". It is off by default and takes effect on the next session you click. Desktop only — the mobile layout always uses the normal inline panel.

How it behaves

How it works

• When the toggle is ON and you click a session in the sidebar, the Dashboard stages that session (stagedSessionId in the session-presence slice) instead of revealing an inline panel. A host component (IsolatedSessionViewHost.tsx) mounts a single Electron <webview> whose document is the app's own renderer entry in embedded-guest mode (?detached=<sessionId>&embedded=1 → DetachedSessionApp — the same full-parity session shell the Pop Out feature uses: composer, approvals, question widgets, everything).
• Clicking another session does not reload that document: the main process re-points the guest (ISOLATED_VIEW_STAGE → ISOLATED_VIEW_STAGE_LOAD push) and the guest rebinds in place, guarded by a monotonically increasing swap token so rapid back-and-forth clicks can never resurrect a stale session.
• The guest keeps its own warm pool (2026-06-20). It used to tear the panel down on every switch (a brief "Loading…" → re-fetch → re-render → scroll), so switching back to a session you'd just left still "went through a render". Now the guest keeps recently-viewed sessions mounted (hidden) so switching back is an instant reveal, and it pre-builds your most-recent inbox sessions in the background (the shell relays that set) so even a first click into one is instant. Because those panels are no longer mounted heavily in the main process while the view covers the screen, the memory mostly moves to the guest rather than adding.
• The guest receives exactly the pushes a popped-out window would (session events for its pinned session + the small global allowlist), delivered through the same push filter (detached-push-filter.ts), via a window-registry entry with role embedded-session-view.
• Security: the app's standard preload is allowed inside a <webview> ONLY when the src is the app's own renderer entry (exact pairing rule in webview-security.ts); the guest keeps the forced posture (sandbox: true, contextIsolation: true, nodeIntegration: false), and the attach handler registers only a live <webview> guest of the main window.
• Because the embedded view is a normal DOM element, menus, dialogs, and tooltips naturally stack above it — no special z-order machinery.

Failure behavior (never a dead panel)

Any failure — preload bridge missing, attach rejected, staging refused, guest renderer crash — silently clears the staged session, and the normal inline panel mounts on the next render. No error toast: falling back to today's behavior is the recovery.

Kill switches

• The Settings toggle itself (isolatedSessionViewEnabled, default false).
• AMC_DISABLE_ISOLATED_SESSION_VIEW=1 env var — force-OFF regardless of the setting (it can never force the mode ON).

v1 limits

• The guest keeps a small warm pool (active + recently-viewed + your recent inbox set), but only the active session receives live updates; a hidden warm panel refreshes the instant you switch into it. (Making every warm panel live would mean routing pushes to a set, which is security-sensitive — deferred.)
• Desktop only; mobile is untouched.
• A popped-out (detached) session is never staged — Pop Out wins.
• App keyboard shortcuts work while typing/clicking inside the view (fixed 2026-06-11 after a user report): every trusted keydown in the embedded view is forwarded to the main window and runs through the normal shortcut pipeline, so session navigation, Ctrl+T, Ctrl+K, Ctrl+= / Ctrl+- text size and the rest behave exactly as in the inline panel. The one deliberate exception: Ctrl+Z while typing in the view's composer stays the textarea's native text-undo.
• The view follows ALL appearance settings live (fontSize fixed 2026-06-11 after a user report; theme, accent/visual theme, chat depth, and Motion & Polish generalized the same day): changes apply to the embedded view (and pop-outs) the moment they land, no restage needed.
• Right-click works inside the view (fixed 2026-06-11): selected text and the composer get the same styled Copy/Cut/Paste menu as the main window, rendered in the view's own document, with actions applied to the view.
• The brief boot-window race (switching again during the view's very first ~1–2s boot could strand the previous session until the next click) was FIXED 2026-06-11 — the view now reconciles its staged target right after it finishes booting.
• Costs one extra renderer process while staged (measured: ~195MB working set — about the same as one Pop Out window).

Related

• Contract (invariants + locking tests): .claude/memory/contracts/isolated-session-view-contract.md
• Pop Out (the same guest shell in its own OS window): detached-session-window.md
• The inline panel's own switch optimizations: inbox-prerender.md, instant-new-session.md