diffplug · nedtwigg · Jul 7, 2026 · Jul 7, 2026 · Jul 7, 2026 · Jul 7, 2026
diff --git a/AGENTS.md b/AGENTS.md
@@ -31,8 +31,9 @@ The primary job of a spec is to be an accurate reference for the current state o
 Each spec's own `Files` / `Code Map` section is the exhaustive file→spec mapping; the touch points below are the load-bearing areas only.
 
 - **`docs/specs/glossary.md`** — Canonical vocabulary: the **Surface** model (terminal **Session** / **browser** surface), the six Session layers and their states, the `Window ⊃ Workspace ⊃ Pane ⊃ Surface` hierarchy and Workspace union status, transition verbs, invariants I1–I10, and the Liskov contract on Registry APIs. Read this first; every other spec defers to it when naming a state, a surface kind, or a verb.
-- **`docs/specs/layout.md`** — Tiling layout and its interaction model: panes/doors, dockview config, passthrough/command modes, command-mode keyboard dispatch, selection overlay, spatial navigation, minimize/reattach, inline rename, kill confirmation, session lifecycle + persistence recovery, pane animations, and the workspaces-rollout ledger (`## Future`). Touch points: `lib/src/components/Wall.tsx` + `components/wall/`, `Baseboard.tsx` / `Door.tsx` / `TerminalPane.tsx`, the registry/lifecycle/persistence modules in `lib/src/lib/`, and any keyboard/navigation/mode/workspace behavior.
+- **`docs/specs/layout.md`** — Tiling layout and its interaction model: panes/doors, the Lath engine pointer, passthrough/command modes, command-mode keyboard dispatch, selection overlay, spatial navigation, minimize/reattach, inline rename, kill confirmation, session lifecycle + persistence recovery, pane animations, and the workspaces-rollout ledger (`## Future`). The tiling engine internals live in tiling-engine.md; layout.md owns the interaction model on top. Touch points: `lib/src/components/Wall.tsx` + `components/wall/`, `Baseboard.tsx` / `Door.tsx` / `TerminalPane.tsx`, the registry/lifecycle/persistence modules in `lib/src/lib/`, and any keyboard/navigation/mode/workspace behavior.
 - **`docs/specs/shortcuts.md`** — Quick-reference table of every keyboard shortcut by mode/context. layout.md owns the behavior; update both when a binding changes.
+- **`docs/specs/tiling-engine.md`** — **Lath**, Dormouse's in-house headless tiling engine (it replaced dockview-react; the dependency is gone). Owns the engine internals: the pure core (split-tree model + `layout()`, the op set with Door restore tokens, sash/neighbor/autoEdge geometry, the headless animator, hierarchical hit-testing), the never-re-parent LathHost adapter with native motion and depth-cycling pointer DnD, the wall store + engine, the pane props contract, and Lath-only persistence with a one-way legacy-blob migration reader. layout.md owns the interaction model on top. Touch points: `lib/src/lib/lath/`, the `lath-*` modules + `LathHost.tsx` in `lib/src/components/wall/`, `Wall.tsx`.
 - **`docs/specs/alert.md`** — The Activity layer: WATCHING / protocol / command-exit alert tracks, attention model, TODO lifecycle, bell + TODO UI states, notification protocols (`OSC 9` / `9;4` / `99` / `777` / `BEL`) with sanitization and security rules, and the Workspace union projection. layout.md defers to it for all alert/TODO behavior. Touch points: `activity-monitor.ts`, `alert-manager.ts`, notification parsing in `terminal-protocol.ts`, the bell/TODO UI in pane headers and Doors.
 - **`docs/specs/terminal-state.md`** — Per-Session semantic state: CWD, prompt/editing/running/finished lifecycle, command runs, title candidates + header derivation, grouping keys, and the keystroke fallback for shells without OSC integration. Touch points: `terminal-state.ts`, `terminal-state-store.ts`, semantic event parsing in `terminal-protocol.ts`, derived pane/door labels.
 - **`docs/specs/terminal-escapes.md`** — Registry of every escape sequence Dormouse parses, answers, or deliberately ignores: OSC/CSI tables pointing at the owning spec, parsing location + `pty:data` strip semantics, replay-time report filtering, iTerm2 identity, and shell-integration injection. Touch points: OSC/CSI parsing at the PTY data boundary, `terminal-report-filter.ts`, `mouse-mode-observer.ts`, `standalone/sidecar/shell-integration/`, or adding any new escape sequence.

diff --git a/docs/specs/dor-browser.md b/docs/specs/dor-browser.md
@@ -5,7 +5,7 @@
 > shared `dor` CLI, surface handle model, and host control plumbing this surface
 > builds on.
 
-Dormouse has one dockview component for web content: `BrowserPanel`, persisted as
+Dormouse has one body component for web content: `BrowserPanel`, persisted as
 `surfaceType: 'browser'` with a swappable `renderMode`.
 
 Entry points:
@@ -60,9 +60,10 @@ Invariants:
   navigations initiated by Dormouse chrome.
 - Agent-browser session state is flat (`session`, `wsPort`, `binaryPath`,
   `syncEngaged`, `key`), not nested.
-- Every browser panel uses dockview `renderer: 'always'`, because moving iframe
-  DOM reloads it and moving the screencast canvas mid-click breaks click
-  synthesis.
+- The browser DOM is never moved: Lath's leaf div is never re-parented, so an
+  embedded `<iframe>` never reloads and the screencast canvas never moves
+  mid-click (which would break click synthesis). This replaces the old dockview
+  `renderer: 'always'` workaround — the constraint is gone at the root, not healed.
 
 Source of truth: `BrowserPanel.tsx`, `browser-surface.ts`, `Wall.tsx`
 (`rendererForParams`, `replaceSurface`), `AgentBrowserPanel.tsx`
@@ -241,19 +242,19 @@ canvas, feeds params/visibility, forwards DOM input, and subscribes to one
 snapshot via `useSyncExternalStore`. The controller owns one
 `AgentBrowserConnection` for `{ session, streamPort, binaryPath }` paired with
 its screenshot loop, and it is SURFACE-scoped rather than panel-scoped: it
-survives panel unmount (minimize, dockview layout churn, React StrictMode). So
+survives panel unmount (minimize, layout churn, React StrictMode). So
 minimize no longer synchronously disposes the connection — the view detaches,
 which counts as hidden and parks the connection after the ~1s debounce, reaching
 the same zero-resource end state with less thrash. The agent-browser
 daemon/session stays alive throughout and reattaches from persisted params. The
 controller's client resources are released only at pane kill or a render swap
 away from the renderer (`disposeAgentBrowserSurfaceController` in `Wall.tsx`).
 
-Hidden-but-mounted panes park too. Browser panels use `renderer: 'always'`, so
-an inactive dockview tab or a backgrounded window stays mounted and would keep
-its ~20Hz stream plus per-pulse screenshot loop running for nothing. A pane that
-goes off-screen — or whose view unmounts (minimize) — parks after a ~1s debounce
-(so quick tab-flipping or a StrictMode remount doesn't thrash the connection):
+Hidden-but-mounted panes park too. A Lath leaf is always mounted (no active-tab
+gating), so a backgrounded window would keep its ~20Hz stream plus per-pulse
+screenshot loop running for nothing. A pane that goes off-screen — or whose view
+unmounts (minimize) — parks after a ~1s debounce (so a quick visibility flip or a
+StrictMode remount doesn't thrash the connection):
 the connection and screenshot loop are disposed while the daemon/session stays
 alive, and daemon-side frame streaming stops on its own because clients trigger
 it. Parking also clears the controller's "this stream port opened live" marker,
@@ -438,8 +439,8 @@ Source of truth: `IFRAME_SHIM` in
 - `registerSurfaceFocusHandle` focuses/blurs the iframe element like other
   surfaces.
 - `IframePanel` applies `transform: translateZ(0)` to its immediate container to
-  avoid Chromium out-of-process iframe pointer offsets caused by dockview
-  containment.
+  avoid Chromium out-of-process iframe pointer offsets from a far-away
+  compositing/containing ancestor.
 - The iframe sandbox omits `allow-top-navigation` to block framebusting while
   allowing scripts, same-origin within the proxy origin, forms, popups, modals,
   downloads, and common device/clipboard permissions.
@@ -513,7 +514,7 @@ Source of truth: `lib/src/lib/platform/types.ts`,
 When changing browser-surface behavior:
 
 - `renderMode` is canonical. Never reintroduce `surfaceType: 'iframe' | 'agent-browser'` or `poppedOut` as stored state — extend the `resolveRenderMode` migration instead, and update the kind-mapping table in `docs/specs/glossary.md` if adding a render mode.
-- Every browser panel keeps dockview `renderer: 'always'` — moving iframe DOM reloads it, and moving the screencast canvas mid-click breaks click synthesis.
+- Never move a browser surface's DOM. Lath's leaf div is never re-parented, so an `<iframe>` never reloads and the screencast canvas never moves mid-click (which would break click synthesis) — do not add any re-parenting/reordering that would defeat this.
 - A new agent-browser subcommand must be added to `AGENT_BROWSER_ALLOWED_SUBCOMMANDS` (`lib/src/lib/platform/types.ts`); the host-side allowlist is the security boundary, not the CLI.
 - External-binary spawns go through `spawnAndCapture` (`dor-lib-common`), never raw `child_process` — see `docs/specs/dor-cli.md` → Spawning External Binaries.
 - New kill/swap/teardown paths must run `closeAgentBrowserSession` **and** dispose the surface controller (`disposeAgentBrowserSurfaceController`), and respect the closed-session mark so pop-out auto-revert cannot resurrect a killed session.

diff --git a/docs/specs/dor-cli.md b/docs/specs/dor-cli.md
@@ -22,7 +22,7 @@ Source of truth:
 | Standalone staging/runtime env | `standalone/package.json`, `standalone/src-tauri/src/lib.rs`, `standalone/sidecar/pty-core.js`, `standalone/sidecar/main.js` |
 | VS Code staging/runtime env | `vscode-ext/package.json`, `vscode-ext/src/pty-manager.ts`, `vscode-ext/src/pty-host.js` |
 | Control request routing into the webview | `standalone/src/tauri-adapter.ts`, `vscode-ext/src/message-router.ts`, `lib/src/lib/platform/vscode-adapter.ts` |
-| Implemented webview control handler | `lib/src/components/Wall.tsx` |
+| Implemented webview control handler | `lib/src/components/wall/use-dor-control.ts` (the `useDorControl` hook, mounted by `lib/src/components/Wall.tsx`) |
 
 ## Bundling And PATH
 
@@ -203,15 +203,15 @@ Invariants:
 ## Current Implemented Commands
 
 Implemented commands call private `surface.*` control methods. `surface.list`
-derives its response from current Dockview panels plus terminal state/activity
+derives its response from the current visible panes plus terminal state/activity
 snapshots where available, then returns `workspace:1` and `window:1` — it
 reports the single active Workspace (Workspace-aware tagging is staged; see
 [Future](#future)).
 
 Command tails captured after `--` are sent as raw argv arrays (`command:
 string[]`); the host — not `dor` — quotes them for the target shell. `dor`
 cannot know which shell the target surface runs, so it forwards argv unquoted
-and the host (`lib/src/components/Wall.tsx`, `dorCommandString`) detects the
+and the host (`lib/src/components/wall/use-dor-control.ts`, `dorCommandString`) detects the
 target shell, picks a quoting style with
 [`shellCommandKind` / `buildShellCommandForKind`](../../dor/src/commands/shell-quote.ts)
 (`cmd` / `posix` / `powershell`), and renders a single command string used for

diff --git a/docs/specs/glossary.md b/docs/specs/glossary.md
@@ -19,7 +19,7 @@ The unit of *layout* is a **Pane**; the unit of *content* is a **Surface**.
 
 | Term | Is | Owner |
 |---|---|---|
-| **Pane** | A slot in the tiling layout (one dockview panel). Holds one or more Surfaces, exactly one selected. | `lib/src/components/Wall.tsx` (dockview) |
+| **Pane** | A slot in the tiling layout (one Lath leaf). Holds one Surface. | `lib/src/components/Wall.tsx`; the engine per `docs/specs/tiling-engine.md` |
 | **Surface** | The content in a Pane: a **terminal** (a Session) or a **browser** Surface. | `Wall.tsx`; browser surfaces per `docs/specs/dor-browser.md` |
 
 Today every Pane holds exactly one Surface, but the model reserves multiple Surfaces per Pane (a future in-pane surface strip) — which is why a Surface ref (`surface:N`) is distinct from a Pane ref (`pane:N`).
@@ -50,7 +50,7 @@ A **Session** runs the full six-axis model below. A **browser Surface** particip
 | **Activity** | full machine (ring + TODO) | **TODO only** — a user may flag it; it never auto-rings (no BEL/OSC source) |
 | **Snapshot** | scrollback, cwd, alert | its `surfaceType` + render params (`docs/specs/transport.md`) |
 | **Process** | PTY (`Live`/`Exited`/`Tombstoned`/`Absent`) | none — host lifetime is the agent-browser session or proxy grant, keyed outside the Pane id |
-| **Registry** | xterm Terminal + persistent DOM element | none — DOM owned by dockview (`renderer:'always'`); focus via a lightweight handle |
+| **Registry** | xterm Terminal + persistent DOM element | none — DOM hosted by LathHost's leaf div (never re-parented); focus via a lightweight handle |
 | **Link** | resume / replay over the live PTY | none — rebuilt from persisted params, not replayed |
 
 The containment hierarchy the `dor` CLI handle model commits to (`docs/specs/dor-cli.md`):
@@ -59,7 +59,7 @@ The containment hierarchy the `dor` CLI handle model commits to (`docs/specs/dor
 Window ⊃ Workspace ⊃ Pane ⊃ Surface  (terminal = Session | browser)
 ```
 
-**Surface identity:** a Surface's id is its dockview panel id. For a terminal Surface that id *is* the `SessionId` and is stable (I1). A browser Surface's id is **not** preserved across a render-mode swap: switching `iframe` ⇄ `ab-screencast` ⇄ `ab-popout` replaces the Surface in the same Pane slot (new id), preserving only the slot and target URL (`docs/specs/dor-browser.md`).
+**Surface identity:** a Surface's id is its Lath leaf id. For a terminal Surface that id *is* the `SessionId` and is stable (I1). A browser Surface's id is **not** preserved across a render-mode swap: switching `iframe` ⇄ `ab-screencast` ⇄ `ab-popout` replaces the Surface in the same Pane slot (new id), preserving only the slot and target URL (`docs/specs/dor-browser.md`).
 
 ## Containers
 
@@ -68,7 +68,7 @@ A Surface never floats free: it sits in a **Pane**, every Pane belongs to exactl
 | Container | Holds | Owner |
 |---|---|---|
 | **Window** | One or more Workspaces. The OS frame (the standalone Tauri window) or the host frame (a VS Code window). | host (Tauri / VS Code) |
-| **Workspace** | A named set of Panes and their Surfaces, plus the layout that arranges them (dockview snapshot + doors). Exactly one **Wall** renders one Workspace. | `lib/src/components/Wall.tsx` at render time; persisted per `docs/specs/transport.md` |
+| **Workspace** | A named set of Panes and their Surfaces, plus the layout that arranges them (Lath layout snapshot + doors). Exactly one **Wall** renders one Workspace. | `lib/src/components/Wall.tsx` at render time; persisted per `docs/specs/transport.md` |
 
 A **Workspace** is the durable grouping a user thinks of as "a window's worth of panes." It has a `WorkspaceId`, a user-facing `name`, the Surfaces it contains, and the layout that arranges them. The pre-workspace model had exactly one implicit Workspace per Window; the model now allows several.
 
@@ -139,7 +139,7 @@ A **Session** is the tuple of its `SessionId` plus one state per layer. `Session
 
 | State | Meaning |
 |---|---|
-| `Paned` | Rendered as a pane in the content area (dockview group) |
+| `Paned` | Rendered as a pane in the content area (a Lath leaf) |
 | `Zoomed` | Subset of `Paned` — the selected pane is maximized |
 | `Doored` | Rendered as a door on the baseboard |
 | `Hidden` | In neither pane nor door — the webview is closed, the Surface belongs to an inactive Workspace (standalone), or the Surface is mid-transition. Process and Activity are unaffected. |
@@ -241,7 +241,7 @@ Use glossary names instead of these. The left column retains a meaning only wher
 | **session** | The durable identity of a **terminal Surface**. Do not use it for the Activity projection (that is `ActivityState`, not `SessionUiState`), nor for the agent-browser daemon's lowercase `session` string (`dormouse.1.<key>`), which is not a Dormouse durable unit. |
 | **terminal** | Keeps its meaning for the `xterm.Terminal` instance. Prose meaning "the whole thing" is **Session** (a terminal Surface). |
 | **surface** | A glossary term, not retired: the durable occupant of a Pane (a terminal Session or a browser Surface). Use **Session** only for the terminal kind; use **Surface** when a statement holds for both. |
-| **panel / pane** | Prefer **pane** for the layout slot. Use "panel" only when quoting dockview's own API (`api.panels`, `addPanel`). |
+| **panel / pane / leaf** | Prefer **pane** for the layout slot; **leaf** is Lath's tree node for the same thing (they map 1:1). "panel" survives only in legacy persisted-blob field names. |
 | **tether** | Remote-control term only: a display showing "tethering to \<device\>" has ceded terminal size authority to a remote viewer (`docs/specs/remote-api.md`). Not a layout term — do not use it for Pane/Door relationships. |
 
 Remote-only vocabulary (**Viewer**, the wire-level `DirectoryEntry` projection) is defined in `docs/specs/remote-api.md` § Terminology.