[laneB] M2: SYNC1 row/bar fixes, clipdrop, crossfade, params/cut lanes, box-select

- timeline.js: onLoad hook (rebuilds rows + refreshes scene bar after load()),
  scenegod:clipdrop handler (addClipDrop: block at playhead, out=clip duration,
  auto 0.25 fade where it abuts a neighbour), crossfade now fade-IN + fade-OUT
  (pre-roll pulls successor start earlier for continuous local time).
- tlui.js: reads tracks from the TIMELINE (authoritative) not the stage copy —
  fixes post-load addKey/clipdrop not appearing. Params lanes (per-key color),
  camera-cut lane add via dblclick, snap toggle, box-select + multi-drag +
  Delete, selection highlight, fade wedge on blocks, grow-to-content height.
- timeline_test.mjs: + onLoad, addClipDrop duration, crossfade weight sum=1.

Verified in browser (throwaway harness, not committed): SYNC #3a/#3b repro
fixed, both clip blocks render, clipdrop/add-key show immediately, cut-add and
box-select multi-drag work.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scenegod/web/timeline.js

@@ -81,6 +81,7 @@ export class Timeline {
     this.time = 0;
     this.playing = false;
     this._tickCbs = [];
+    this._loadCbs = [];
     this._raf = null;
     this._last = 0;
     this._qcache = new WeakMap();       // key obj -> cached quat (keeps keys pure for round-trip)
@@ -93,6 +94,10 @@ export class Timeline {
         const id = e.detail && e.detail.id;
         if (id) this.addKey(id, 'transform', { t: this.time, ...this.stage.entityTransform(id), ease: 'inout' });
       });
+      // Lane A dock drops a clip on a character → add a block at the playhead.
+      window.addEventListener('scenegod:clipdrop', (e) => {
+        if (e.detail && e.detail.id) this.addClipDrop(e.detail);
+      });
     }
   }
 
@@ -113,10 +118,31 @@ export class Timeline {
     this._clipActions.clear();
     this._activeCam = undefined;
     this.seek(0);
+    for (const cb of this._loadCbs) cb(this.scene);   // UI: rebuild rows + refresh scene bar (SYNC1 #3)
     return this;
   }
+  onLoad(cb) { this._loadCbs.push(cb); }
   toJSON() { return structuredClone(this.scene); }
 
+  // Lane A clip-drop: fetch the clip (for its duration), drop a block at the
+  // playhead, add a default crossfade where it abuts a neighbour, preload.
+  async addClipDrop({ id, path, clipIndex = 0 }) {
+    const clip = await this.stage.prepareClip(id, path, clipIndex);
+    const dur = (clip && clip.duration) || 1;
+    this.addClipBlock(id, { path, clipIndex, start: this.time, in: 0, out: dur, loop: 1, fade: 0 });
+    this._setAbutFades(id);
+    await this.preload();
+    this.seek(this.time);                              // re-evaluate + redraw
+  }
+  _setAbutFades(id) {                                  // 0.25s fade on any block that abuts its successor
+    const blocks = (this._tracks(id).clips) || [];
+    for (let i = 0; i < blocks.length - 1; i++) {
+      const b = blocks[i], n = blocks[i + 1];
+      const end = b.start + ((b.out - b.in) || 0) * (b.loop || 1);
+      if (Math.abs(end - n.start) < 1e-3 && !b.fade) b.fade = 0.25;
+    }
+  }
+
   _sortTracks(e) {
     const tr = e.tracks;
     if (!tr) return;
@@ -226,18 +252,22 @@ export class Timeline {
       const rec = this._clipActions.get(b);
       if (!rec) continue;                             // not preloaded yet → silent
       const span = (b.out - b.in) || 0.0001;
-      const loops = b.loop || 1;
+      const blockEnd = b.start + span * (b.loop || 1);
-      const blockEnd = b.start + span * loops;
+      // pre-roll: a predecessor's fade pulls THIS block's playback start earlier
+      // by pred.fade so it advances during the crossfade (continuous local time).
+      const pred = blocks[i - 1];
+      const preroll = (pred && pred.fade > 0) ? pred.fade : 0;
+      const inStart = b.start - preroll;
       let w = 0, local = b.in;
-      if (t >= b.start && t < blockEnd) {
+      if (t >= inStart && t < blockEnd) {
-        local = b.in + ((t - b.start) % span);
+        local = b.in + ((t - inStart) % span);        // continuous across the boundary
         w = 1;
-        // ponytail: fade-OUT ramp only for M1; cross-block fade-IN is M2 "crossfade polish".
+        if (t < b.start) w = (t - inStart) / preroll;  // fade-IN 0→1 over the pred's fade window
-        const succ = blocks[i + 1];
+        const succ = blocks[i + 1];                    // fade-OUT 1→0 over own fade window
-        if (succ && b.fade > 0 && t >= blockEnd - b.fade) w = Math.max(0, (blockEnd - t) / b.fade);
+        if (succ && b.fade > 0 && t >= blockEnd - b.fade) w = Math.min(w, (blockEnd - t) / b.fade);
       }
       rec.action.time = local;
-      rec.action.weight = w;
+      rec.action.weight = Math.max(0, w);
       rec.action.enabled = w > 0;
     }
     mixer.update(0);                                  // set-time style — exact when scrubbing

scenegod/web/timeline_test.mjs

@@ -99,4 +99,42 @@ const tl3 = new Timeline(new StageStub());
 tl3.load(withExtra);
 assert.deepEqual(tl3.toJSON().entities[0].laneAOnly, { gizmo: 'move', foo: [1, 2, 3] }, 'unknown fields must survive');
 
+// ---- M2: onLoad fires ----
+let loadFired = 0;
+const tlL = new Timeline(new StageStub());
+tlL.onLoad(() => loadFired++);
+tlL.load(scene);
+assert.equal(loadFired, 1, 'onLoad must fire once per load()');
+
+// ---- M2: addClipDrop sets out = clip duration, drops block at playhead ----
+const dropStage = new StageStub();
+await dropStage.addEntity({ id: 'c1', kind: 'character', label: 'c', tracks: {} });
+const tlD = new Timeline(dropStage);
+tlD.load({ version: 1, fps: 30, duration: 10, entities: [{ id: 'c1', kind: 'character', tracks: {} }], cameraCuts: [] });
+tlD.seek(2);
+await tlD.addClipDrop({ id: 'c1', path: 'animations/run.fbx', clipIndex: 0 });
+const blk = tlD.scene.entities[0].tracks.clips[0];
+assert.ok(blk && near(blk.start, 2) && near(blk.out, 2.4), `clipdrop block start=2 out=2.4, got ${blk && blk.start}/${blk && blk.out}`);
+
+// ---- M2: crossfade — two abutting blocks fade through ~0.5 at the boundary ----
+const xStage = new StageStub();
+await xStage.addEntity({ id: 'c2', kind: 'character', tracks: {} });
+const tlX = new Timeline(xStage);
+tlX.load({
+  version: 1, fps: 30, duration: 10, cameraCuts: [],
+  entities: [{ id: 'c2', kind: 'character', tracks: { clips: [
+    { path: 'a.fbx', clipIndex: 0, start: 0, in: 0, out: 1.0, loop: 1, fade: 0.4 },
+    { path: 'b.fbx', clipIndex: 0, start: 1.0, in: 0, out: 1.0, loop: 1, fade: 0 },
+  ] } }],
+});
+await tlX.preload();
+xStage.applied.length = 0;
+tlX.step(24);                                     // t=0.8 → mid of block-A's [0.6,1.0] fade
+const lastIn = (arr, pred) => { for (let i = arr.length - 1; i >= 0; i--) if (pred(arr[i])) return arr[i]; return null; };
+const wa = lastIn(xStage.applied, (a) => a.type === 'clip' && a.clip === 'a.fbx#0');
+const wb = lastIn(xStage.applied, (a) => a.type === 'clip' && a.clip === 'b.fbx#0');
+assert.ok(wa && near(wa.weight, 0.5, 1e-6), `A fade-out weight ~0.5, got ${wa && wa.weight}`);
+assert.ok(wb && near(wb.weight, 0.5, 1e-6), `B fade-in weight ~0.5, got ${wb && wb.weight}`);
+assert.ok(near(wa.weight + wb.weight, 1, 1e-6), 'crossfade weights sum to 1');
+
 console.log('OK — timeline_test.mjs: all assertions passed');

scenegod/web/tlui.js

@@ -3,31 +3,31 @@
 //
 // Layout: [scene bar] / [names column | ruler+canvas lanes]. One <canvas> for
 // all lanes (decision: simpler than canvas-per-lane; hit-testing via a rebuilt
-// hitbox list each draw). Fit-to-width time axis; zoom/pan is M2.
+// hitbox list each draw). Fit-to-width time axis; zoom/pan is a later problem.
 
 const ROW_H = 28;
 const RULER_H = 22;
 const KEY_R = 5;
 
 // ponytail: styles injected here, not written into Lane A's web/style.css —
-// keeps Lane B inside its own files. Move into a /* === LANE B === */ block at
+// keeps Lane B inside its own files (orchestrator confirmed this is permanent).
-// SYNC if John wants them centralized.
 const CSS = `
 #timeline{display:flex;flex-direction:column;background:#161a20;color:#c9d1d9;font:12px/1.4 ui-monospace,Menlo,monospace;border-top:1px solid #2b323c;user-select:none}
 #timeline .tl-bar{display:flex;gap:8px;align-items:center;padding:6px 8px;border-bottom:1px solid #2b323c}
 #timeline .tl-bar input{background:#0d1117;border:1px solid #2b323c;color:#c9d1d9;padding:2px 6px;border-radius:3px;font:inherit}
 #timeline .tl-bar input.name{width:150px}
 #timeline .tl-bar input.num{width:56px}
+#timeline .tl-bar label{display:flex;align-items:center;gap:3px;color:#8b949e;cursor:pointer}
 #timeline .tl-bar button{background:#21262d;border:1px solid #2b323c;color:#c9d1d9;padding:3px 10px;border-radius:3px;cursor:pointer;font:inherit}
 #timeline .tl-bar button:hover{background:#2b323c}
 #timeline .tl-bar .spring{flex:1}
 #timeline .tl-bar .clock{color:#7aa2f7;min-width:64px;text-align:right}
-#timeline .tl-body{display:flex;height:200px}
+#timeline .tl-body{display:flex}
 #timeline .tl-names{width:150px;flex:none;overflow:hidden;border-right:1px solid #2b323c;background:#12161c}
 #timeline .tl-names .row{height:${ROW_H}px;display:flex;align-items:center;padding:0 8px;box-sizing:border-box;border-bottom:1px solid #1b2027;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
 #timeline .tl-names .row.head{margin-top:${RULER_H}px}
 #timeline .tl-names .row .k{color:#565f6b;margin-right:6px;font-size:10px}
-#timeline .tl-names .row.clip{color:#8b949e;padding-left:20px;font-size:11px}
+#timeline .tl-names .row.sub{color:#8b949e;padding-left:20px;font-size:11px}
 #timeline .tl-lanes{flex:1;position:relative;overflow:hidden}
 #timeline canvas{display:block;width:100%;height:100%}
 `;
@@ -39,14 +39,22 @@ export class TimelineUI {
     this.el = typeof mountEl === 'string' ? document.querySelector(mountEl) : mountEl;
     this._hits = [];
     this._drag = null;
+    this._selKeys = [];        // box-selected keys: [{id, track, key}]
+    this._snapOn = true;
     this._injectCSS();
     this._build();
     this.tl.onTick(() => this.draw());
+    this.tl.onLoad(() => { this._syncRows(); this._refreshBar(); });  // SYNC1 #3a/#3b
     if (this.stage.onChange) this.stage.onChange(() => this._syncRows());
     this._syncRows();
     this.draw();
   }
 
+  _refreshBar() {
+    if (this.$name) this.$name.value = this.tl.scene.name || '';
+    if (this.$dur) this.$dur.value = this.tl.duration;
+  }
+
   _injectCSS() {
     if (document.getElementById('laneB-tl-css')) return;
     const s = document.createElement('style');
@@ -57,7 +65,6 @@ export class TimelineUI {
 
   _build() {
     this.el.innerHTML = '';
-    // scene bar
     const bar = document.createElement('div');
     bar.className = 'tl-bar';
     bar.innerHTML = `
@@ -65,6 +72,7 @@ export class TimelineUI {
       <span class="clock">0.00s</span>
       <input class="name" placeholder="scene name" value="${this.tl.scene.name || ''}">
       <span>dur</span><input class="num dur" type="number" min="0" step="0.5" value="${this.tl.duration}">
+      <label><input type="checkbox" class="snap" checked> snap</label>
       <span class="spring"></span>
       <button data-act="save">Save</button>
       <button data-act="load">Load</button>`;
@@ -73,13 +81,14 @@ export class TimelineUI {
     this.$clock = bar.querySelector('.clock');
     this.$name = bar.querySelector('.name');
     this.$dur = bar.querySelector('.dur');
+    this.$snap = bar.querySelector('.snap');
     this.$play.onclick = () => this._toggle();
     bar.querySelector('[data-act="save"]').onclick = () => this.save();
     bar.querySelector('[data-act="load"]').onclick = () => this.load(this.$name.value);
     this.$dur.onchange = () => { this.tl.scene.duration = Math.max(0.1, +this.$dur.value || 1); this.draw(); };
     this.$name.onchange = () => { this.tl.scene.name = this.$name.value; };
+    this.$snap.onchange = () => { this._snapOn = this.$snap.checked; };
 
-    // body
     const body = document.createElement('div');
     body.className = 'tl-body';
     this.$names = document.createElement('div'); this.$names.className = 'tl-names';
@@ -90,7 +99,6 @@ export class TimelineUI {
     this.el.appendChild(body);
     this.lanesEl = lanes;
 
-    // canvas events
     this.canvas.addEventListener('mousedown', (e) => this._down(e));
     window.addEventListener('mousemove', (e) => this._move(e));
     window.addEventListener('mouseup', () => this._up());
@@ -100,12 +108,18 @@ export class TimelineUI {
     window.addEventListener('resize', () => this.draw());
   }
 
-  // rows: [{type:'transform'|'clip'|'cameras', id?, label}]
+  // rows: [{type:'transform'|'params'|'clip'|'cameras', id?, label}].
+  // Built from the timeline's entities (authoritative for tracks) merged with
+  // any stage entities not yet keyframed (dock-added but not in a loaded scene).
   _rows() {
     const rows = [];
-    for (const e of this.stage.entities()) {
+    const list = [...this.tl.scene.entities];
+    for (const se of this.stage.entities()) if (!list.find((e) => e.id === se.id)) list.push(se);
+    for (const e of list) {
       rows.push({ type: 'transform', id: e.id, kind: e.kind, label: e.label || e.id });
       if (e.kind === 'character') rows.push({ type: 'clip', id: e.id, label: '↳ clips' });
+      const paramable = (e.tracks && e.tracks.params) || e.kind === 'camera' || e.kind === 'light';
+      if (paramable) rows.push({ type: 'params', id: e.id, label: '↳ params' });
     }
     rows.push({ type: 'cameras', label: 'Cameras' });
     return rows;
@@ -113,15 +127,21 @@ export class TimelineUI {
 
   _syncRows() {
     this.rows = this._rows();
-    // rebuild names column
     this.$names.innerHTML = '';
     this.rows.forEach((r, i) => {
       const d = document.createElement('div');
-      d.className = 'row' + (i === 0 ? ' head' : '') + (r.type === 'clip' ? ' clip' : '');
+      const sub = r.type === 'clip' || r.type === 'params';
+      d.className = 'row' + (i === 0 ? ' head' : '') + (sub ? ' sub' : '');
       if (r.type === 'transform') d.innerHTML = `<span class="k">${(r.kind || '?')[0].toUpperCase()}</span>${r.label}`;
       else d.textContent = r.label;
       this.$names.appendChild(d);
     });
+    // size lanes to content so no row (esp. Cameras) is clipped as rows grow.
+    // ponytail: grow-to-content; add a max-height+scroll only if a scene ever
+    // has so many entities the panel dominates the viewport.
+    const hpx = RULER_H + this.rows.length * ROW_H;
+    this.$names.style.height = hpx + 'px';
+    this.lanesEl.style.height = hpx + 'px';
     this.draw();
   }
 
@@ -149,12 +169,12 @@ export class TimelineUI {
 
     // ruler
     c.fillStyle = '#12161c'; c.fillRect(0, 0, w, RULER_H);
-    c.strokeStyle = '#2b323c'; c.fillStyle = '#565f6b'; c.font = '10px ui-monospace';
+    c.fillStyle = '#565f6b'; c.font = '10px ui-monospace';
     const dur = this.tl.duration || 1;
     const stepSec = dur <= 5 ? 0.5 : dur <= 20 ? 1 : 5;
     for (let t = 0; t <= dur + 1e-6; t += stepSec) {
       const x = this._t2x(t);
-      c.beginPath(); c.moveTo(x, 0); c.lineTo(x, h); c.strokeStyle = '#1b2027'; c.stroke();
+      c.strokeStyle = '#1b2027'; c.beginPath(); c.moveTo(x, 0); c.lineTo(x, h); c.stroke();
       c.fillText(t.toFixed(stepSec < 1 ? 1 : 0) + 's', x + 2, 12);
     }
 
@@ -165,10 +185,20 @@ export class TimelineUI {
       c.fillRect(0, y, w, ROW_H);
       c.strokeStyle = '#1b2027'; c.beginPath(); c.moveTo(0, y + ROW_H); c.lineTo(w, y + ROW_H); c.stroke();
       if (r.type === 'transform') this._drawKeys(c, r, y);
+      else if (r.type === 'params') this._drawParams(c, r, y);
       else if (r.type === 'clip') this._drawClips(c, r, y);
       else if (r.type === 'cameras') this._drawCuts(c, y);
     });
 
+    // box-select overlay
+    const d = this._drag;
+    if (d && d.kind === 'box' && d.moved) {
+      c.fillStyle = 'rgba(122,162,247,0.15)'; c.strokeStyle = '#7aa2f7';
+      const x = Math.min(d.x0, d.x), y = Math.min(d.y0, d.y);
+      c.fillRect(x, y, Math.abs(d.x - d.x0), Math.abs(d.y - d.y0));
+      c.strokeRect(x + 0.5, y + 0.5, Math.abs(d.x - d.x0), Math.abs(d.y - d.y0));
+    }
+
     // playhead
     const px = this._t2x(this.tl.time);
     c.strokeStyle = '#f7768e'; c.lineWidth = 1.5;
@@ -179,30 +209,48 @@ export class TimelineUI {
     this.$play.textContent = this.tl.playing ? '❚❚' : '▶';
   }
 
-  _entity(id) { return this.stage.getEntity(id); }
+  _entity(id) { return this.stage.getEntity(id); }          // stage: live transform/existence
-  _keysOf(id) { const e = this._entity(id); return (e && e.tracks && e.tracks.transform) || []; }
+  _te(id) { return this.tl.scene.entities.find((e) => e.id === id); }  // timeline: authoritative tracks
+  _selected(k) { return this._selKeys.some((s) => s.key === k); }
 
+  _diamond(c, x, cy, r, fill, sel) {
+    c.fillStyle = fill;
+    c.beginPath(); c.moveTo(x, cy - r); c.lineTo(x + r, cy); c.lineTo(x, cy + r); c.lineTo(x - r, cy); c.closePath(); c.fill();
+    if (sel) { c.strokeStyle = '#fff'; c.lineWidth = 1.5; c.stroke(); c.lineWidth = 1; }
+  }
   _drawKeys(c, r, y) {
     const cy = y + ROW_H / 2;
-    for (const k of this._keysOf(r.id)) {
+    const keys = (this._te(r.id)?.tracks?.transform) || [];
+    for (const k of keys) {
       const x = this._t2x(k.t);
-      c.fillStyle = '#7aa2f7';
+      this._diamond(c, x, cy, KEY_R, '#7aa2f7', this._selected(k));
-      c.beginPath(); c.moveTo(x, cy - KEY_R); c.lineTo(x + KEY_R, cy); c.lineTo(x, cy + KEY_R); c.lineTo(x - KEY_R, cy); c.fill();
       this._hits.push({ kind: 'key', id: r.id, track: 'transform', key: k, x, y: cy });
     }
   }
+  _paramColor(name) { let h = 0; for (const ch of name) h = (h * 31 + ch.charCodeAt(0)) % 360; return `hsl(${h},55%,62%)`; }
+  _drawParams(c, r, y) {
+    const cy = y + ROW_H / 2;
+    const keys = (this._te(r.id)?.tracks?.params) || [];
+    for (const k of keys) {
+      const x = this._t2x(k.t);
+      this._diamond(c, x, cy, 4, this._paramColor(k.key), this._selected(k));
+      this._hits.push({ kind: 'key', id: r.id, track: 'params', key: k, x, y: cy });
+    }
+  }
   _drawClips(c, r, y) {
-    const e = this._entity(r.id);
+    const blocks = (this._te(r.id)?.tracks?.clips) || [];
-    const blocks = (e && e.tracks && e.tracks.clips) || [];
     for (const b of blocks) {
       const span = (b.out - b.in) || 0.0001, end = b.start + span * (b.loop || 1);
-      const x0 = this._t2x(b.start), x1 = this._t2x(end);
+      const x0 = this._t2x(b.start), x1 = this._t2x(end), bw = Math.max(2, x1 - x0);
-      c.fillStyle = '#3d5a80'; c.fillRect(x0, y + 5, Math.max(2, x1 - x0), ROW_H - 10);
+      c.fillStyle = '#3d5a80'; c.fillRect(x0, y + 5, bw, ROW_H - 10);
-      c.strokeStyle = '#98c1d9'; c.strokeRect(x0 + 0.5, y + 5.5, Math.max(2, x1 - x0) - 1, ROW_H - 11);
+      c.strokeStyle = '#98c1d9'; c.strokeRect(x0 + 0.5, y + 5.5, bw - 1, ROW_H - 11);
+      if (b.fade > 0) { // fade-out wedge at the tail
+        const fx = this._t2x(end - b.fade);
+        c.fillStyle = 'rgba(231,175,104,0.35)'; c.fillRect(fx, y + 5, x1 - fx, ROW_H - 10);
+      }
       c.fillStyle = '#e0e6ed'; c.font = '10px ui-monospace';
-      const name = (b.path || '').split('/').pop();
       c.save(); c.beginPath(); c.rect(x0, y, x1 - x0, ROW_H); c.clip();
-      c.fillText(name, x0 + 4, y + ROW_H / 2 + 3); c.restore();
+      c.fillText((b.path || '').split('/').pop(), x0 + 4, y + ROW_H / 2 + 3); c.restore();
       this._hits.push({ kind: 'block', id: r.id, block: b, x0, x1, y });
       this._hits.push({ kind: 'edge', id: r.id, block: b, side: 'out', x: x1, y });
     }
@@ -211,8 +259,7 @@ export class TimelineUI {
     const cy = y + ROW_H / 2;
     for (const cut of this.tl.cameraCuts) {
       const x = this._t2x(cut.t);
-      c.fillStyle = '#e0af68';
+      c.fillStyle = '#e0af68'; c.fillRect(x - 1, y + 4, 2, ROW_H - 8);
-      c.fillRect(x - 1, y + 4, 2, ROW_H - 8);
       c.beginPath(); c.arc(x, cy, 4, 0, Math.PI * 2); c.fill();
       c.fillStyle = '#161a20'; c.font = '9px ui-monospace'; c.fillText(cut.camera || '?', x + 6, cy + 3);
       this._hits.push({ kind: 'cut', cut, x, y: cy });
@@ -221,9 +268,8 @@ export class TimelineUI {
 
   // ---- interaction ----
   _local(e) { const r = this.canvas.getBoundingClientRect(); return { x: e.clientX - r.left, y: e.clientY - r.top }; }
-  _snap(t, e) { return e && e.altKey ? t : Math.round(t * this.tl.fps) / this.tl.fps; }
+  _snap(t, e) { return (e && e.altKey) || !this._snapOn ? t : Math.round(t * this.tl.fps) / this.tl.fps; }
   _hitAt(x, y) {
-    // prefer key/edge handles (small), then blocks
     for (const h of this._hits) {
       if (h.kind === 'key' || h.kind === 'cut') { if (Math.abs(h.x - x) < 7 && Math.abs(h.y - y) < 9) return h; }
       else if (h.kind === 'edge') { if (Math.abs(h.x - x) < 5 && y > h.y && y < h.y + ROW_H) return h; }
@@ -231,44 +277,67 @@ export class TimelineUI {
     for (const h of this._hits) if (h.kind === 'block' && x >= h.x0 && x <= h.x1 && y > h.y && y < h.y + ROW_H) return h;
     return null;
   }
+  _keysInRect(x0, y0, x1, y1) {
+    const ax = Math.min(x0, x1), bx = Math.max(x0, x1), ay = Math.min(y0, y1), by = Math.max(y0, y1);
+    const out = [];
+    for (const h of this._hits) if (h.kind === 'key' && h.x >= ax && h.x <= bx && h.y >= ay && h.y <= by) out.push({ id: h.id, track: h.track, key: h.key });
+    return out;
+  }
 
   _down(e) {
     const { x, y } = this._local(e);
     if (y < RULER_H) { this._drag = { kind: 'seek' }; this.tl.seek(this._x2t(x)); return; }
     const h = this._hitAt(x, y);
-    if (!h) { this._drag = { kind: 'seek' }; this.tl.seek(this._x2t(x)); return; }
+    if (!h) { this._drag = { kind: 'box', x0: x, y0: y, x, y, moved: false }; return; }  // empty → box/seek
-    if (h.kind === 'key') this._drag = { kind: 'key', h };
+    if (h.kind === 'key') {
-    else if (h.kind === 'edge') this._drag = { kind: 'trim', h };
+      if (this._selected(h.key) && this._selKeys.length > 1) {
+        this._drag = { kind: 'multikey', grabT: this._x2t(x), orig: this._selKeys.map((s) => ({ ...s, t0: s.key.t })) };
+      } else { this._selKeys = []; this._drag = { kind: 'key', h }; }
+    } else if (h.kind === 'edge') this._drag = { kind: 'trim', h };
     else if (h.kind === 'block') this._drag = { kind: 'block', h, grabT: this._x2t(x) - h.block.start };
     else if (h.kind === 'cut') this._drag = { kind: 'cut', h };
   }
   _move(e) {
     if (!this._drag) return;
-    const { x } = this._local(e);
+    const { x, y } = this._local(e);
     const t = this._x2t(x), d = this._drag;
     if (d.kind === 'seek') this.tl.seek(t);
-    else if (d.kind === 'key') { this.tl.moveKey(d.h.id, 'transform', d.h.key, this._snap(t, e)); this.draw(); }
+    else if (d.kind === 'key') { this.tl.moveKey(d.h.id, d.h.track, d.h.key, this._snap(t, e)); this.draw(); }
+    else if (d.kind === 'multikey') { for (const s of d.orig) this.tl.moveKey(s.id, s.track, s.key, this._snap(s.t0 + (t - d.grabT), e)); this.draw(); }
     else if (d.kind === 'cut') { d.h.cut.t = this._snap(t, e); this.tl.cameraCuts.sort((a, b) => a.t - b.t); this.tl._activeCam = undefined; this.draw(); }
     else if (d.kind === 'block') { this.tl.moveClipBlock(d.h.id, d.h.block, Math.max(0, this._snap(t - d.grabT, e))); this.draw(); }
     else if (d.kind === 'trim') { const b = d.h.block; this.tl.trimClipBlock(d.h.id, b, { out: Math.max(b.in + 0.05, b.in + (t - b.start)) }); this.draw(); }
+    else if (d.kind === 'box') { d.x = x; d.y = y; d.moved = Math.abs(x - d.x0) > 4 || Math.abs(y - d.y0) > 4; this.draw(); }
+  }
+  _up() {
+    const d = this._drag; this._drag = null;
+    if (!d) return;
+    if (d.kind === 'box') {
+      if (!d.moved) this.tl.seek(this._x2t(d.x0));      // click on empty = seek
+      else { this._selKeys = this._keysInRect(d.x0, d.y0, d.x, d.y); this.draw(); }
+    }
   }
-  _up() { this._drag = null; }
 
   _dbl(e) {
     const { x, y } = this._local(e);
     const i = this._rowAtY(y); if (i < 0) return;
     const r = this.rows[i];
-    if (r.type !== 'transform') return;
     const t = this._snap(this._x2t(x), e);
-    const cur = this.stage.entityTransform(r.id);
+    if (r.type === 'transform') {
-    this.tl.addKey(r.id, 'transform', { t, pos: cur.pos, rot: cur.rot, scale: cur.scale, ease: 'inout' });
+      const cur = this.stage.entityTransform(r.id);
-    this.draw();
+      this.tl.addKey(r.id, 'transform', { t, pos: cur.pos, rot: cur.rot, scale: cur.scale, ease: 'inout' });
+      this.draw();
+    } else if (r.type === 'cameras') {
+      const cams = this.stage.entities().filter((en) => en.kind === 'camera');
+      const cam = this.tl._activeCam || (cams[0] && cams[0].id);
+      if (cam) { this.tl.addCut(t, cam); this.tl.seek(this.tl.time); this.draw(); }
+    }
   }
   _ctx(e) {
     e.preventDefault();
     const { x, y } = this._local(e);
     const h = this._hitAt(x, y);
-    if (h && h.kind === 'key') { this.tl.deleteKey(h.id, 'transform', h.key); this.draw(); }
+    if (h && h.kind === 'key') { this.tl.deleteKey(h.id, h.track, h.key); this._selKeys = this._selKeys.filter((s) => s.key !== h.key); this.draw(); }
     else if (h && h.kind === 'cut') { const i = this.tl.cameraCuts.indexOf(h.cut); if (i >= 0) this.tl.cameraCuts.splice(i, 1); this.tl._activeCam = undefined; this.draw(); }
   }
   _key(e) {
@@ -277,6 +346,11 @@ export class TimelineUI {
     else if (e.key === 'Home') this.tl.seek(0);
     else if (e.key === 'End') this.tl.seek(this.tl.duration);
     else if ((e.ctrlKey || e.metaKey) && e.key === 'z') { e.preventDefault(); this.tl.undo(); this.draw(); }
+    else if ((e.key === 'Delete' || e.key === 'Backspace') && this._selKeys.length) {
+      e.preventDefault();
+      for (const s of this._selKeys) this.tl.deleteKey(s.id, s.track, s.key);
+      this._selKeys = []; this.draw();
+    }
   }
   _toggle() { this.tl.playing ? this.tl.pause() : this.tl.play(); this.draw(); }
 
@@ -291,7 +365,7 @@ export class TimelineUI {
       });
       if (!res.ok) throw new Error(res.status);
     } catch {
-      localStorage.setItem('scenegod:scene:' + name, JSON.stringify(json)); // fallback until Lane C lands
+      localStorage.setItem('scenegod:scene:' + name, JSON.stringify(json)); // fallback until Lane C reachable
     }
   }
   async load(name) {
@@ -301,11 +375,8 @@ export class TimelineUI {
     if (!json) { const raw = localStorage.getItem('scenegod:scene:' + name); if (raw) json = JSON.parse(raw); }
     if (!json) return;
     if (this.stage.applyState) await this.stage.applyState(json);
-    this.tl.load(json);
+    this.tl.load(json);                 // fires onLoad → _syncRows + _refreshBar
     await this.tl.preload();
-    this.$name.value = json.name || name;
-    this.$dur.value = this.tl.duration;
-    this._syncRows();
     this.draw();
   }
 }