package.json

@@ -28,7 +28,7 @@
       { "command": "cowriting.reply", "title": "Reply", "category": "Cowriting" },
       { "command": "cowriting.resolveThread", "title": "Resolve Thread", "category": "Cowriting" },
       { "command": "cowriting.reopenThread", "title": "Reopen Thread", "category": "Cowriting" },
-      { "command": "cowriting.toggleAttribution", "title": "Cowriting: Toggle Attribution", "category": "Cowriting" },
+      { "command": "cowriting.toggleAttribution", "title": "Toggle Attribution", "category": "Cowriting" },
       { "command": "cowriting.applyAgentEdit", "title": "Apply Agent Edit (internal seam)", "category": "Cowriting" }
     ],
     "menus": {

src/attributionController.ts

@@ -31,6 +31,12 @@ interface DocAttribution {
   orphans: AttributionRecord[];
   /** record metadata per live span id (updatedAt bookkeeping). */
   records: Map<string, AttributionRecord>;
+  /**
+   * true once this doc has had any span/record this session — lets save persist
+   * deliberate deletion to empty (so stale records don't come back as phantom
+   * orphans on reload).
+   */
+  hadAttributions: boolean;
 }
 
 const AGENT_DECO: vscode.DecorationRenderOptions = {
@@ -77,7 +83,7 @@ export class AttributionController implements vscode.Disposable {
   private state(docPath: string): DocAttribution {
     let s = this.docs.get(docPath);
     if (!s) {
-      s = { docPath, spans: [], orphans: [], records: new Map() };
+      s = { docPath, spans: [], orphans: [], records: new Map(), hadAttributions: false };
       this.docs.set(docPath, s);
     }
     return s;
@@ -110,6 +116,7 @@ export class AttributionController implements vscode.Disposable {
         }
       }
       s.spans = coalesce(s.spans);
+      if (artifact.attributions.length > 0) s.hadAttributions = true;
     }
     this.render(document);
   }
@@ -135,7 +142,9 @@ export class AttributionController implements vscode.Disposable {
       return;
     }
     const s = this.state(docPath);
-    for (const change of e.contentChanges) {
+    // Sort descending by offset so earlier changes don't invalidate later offsets
+    // (VS Code's order is undocumented; defensive sort is the safe guarantee).
+    for (const change of [...e.contentChanges].sort((a, b) => b.rangeOffset - a.rangeOffset)) {
       const edit = {
         start: change.rangeOffset,
         end: change.rangeOffset + change.rangeLength,
@@ -149,6 +158,7 @@ export class AttributionController implements vscode.Disposable {
         turnId: hit?.turnId,
       });
     }
+    if (s.spans.length > 0) s.hadAttributions = true;
     this.render(e.document);
   }
 
@@ -193,7 +203,10 @@ export class AttributionController implements vscode.Disposable {
     if (!this.isTracked(document)) return;
     const docPath = this.docPathOf(document.uri);
     const s = this.docs.get(docPath);
-    if (!s || (s.spans.length === 0 && s.orphans.length === 0)) return;
+    // Allow save when hadAttributions is true even if spans/orphans are now empty:
+    // that means the user deliberately deleted all attributed text, and we must
+    // persist a.attributions=[] so stale records don't return as phantom orphans.
+    if (!s || (!s.hadAttributions && s.spans.length === 0 && s.orphans.length === 0)) return;
     const text = document.getText();
     const now = new Date().toISOString();
     const records: AttributionRecord[] = [];
@@ -239,14 +252,21 @@ export class AttributionController implements vscode.Disposable {
   }
 
   private render(document: vscode.TextDocument): void {
-    const editor = vscode.window.visibleTextEditors.find((e) => e.document === document);
-    if (!editor || !this.isTracked(document)) return;
+    if (!this.isTracked(document)) return;
     const s = this.docs.get(this.docPathOf(document.uri));
     const spans = this.visible && s ? s.spans : [];
     const toRange = (sp: LiveSpan) =>
       new vscode.Range(document.positionAt(sp.start), document.positionAt(sp.end));
-    editor.setDecorations(this.agentType, spans.filter((x) => x.author.kind === "agent").map(toRange));
-    editor.setDecorations(this.humanType, spans.filter((x) => x.author.kind === "human").map(toRange));
+    const agentRanges = spans.filter((x) => x.author.kind === "agent").map(toRange);
+    const humanRanges = spans.filter((x) => x.author.kind === "human").map(toRange);
+    // Apply decorations to ALL visible split-editors showing this document, not
+    // just the first match — each editor pane has its own decoration layer.
+    for (const editor of vscode.window.visibleTextEditors) {
+      if (editor.document === document) {
+        editor.setDecorations(this.agentType, agentRanges);
+        editor.setDecorations(this.humanType, humanRanges);
+      }
+    }
     this.renderStatus(s);
   }
 

src/store.ts

@@ -11,19 +11,33 @@ import * as path from "node:path";
 import { emptyArtifact, serializeArtifact, type Artifact } from "./model";
 
 export class CoauthorStore {
-  /** sidecar paths this store just wrote, so the shared watcher can ignore them. */
-  private readonly selfWrites = new Set<string>();
+  /**
+   * Pending-write counts keyed by absolute sidecar path. A Map (not Set) because
+   * one doc save can trigger TWO store.update() calls (ThreadController then
+   * AttributionController), both writing the same sidecar — a Set would let the
+   * second watcher event leak through as "external" (comment-UI flicker).
+   */
+  private readonly selfWrites = new Map<string, number>();
 
   /** @param rootDir absolute workspace-folder root that owns the `.threads/` tree. */
   constructor(private readonly rootDir: string) {}
 
   /**
-   * Delete-and-report: true iff `fsPath` was a sidecar we just wrote via
-   * `update`. The shared watcher (extension.ts) calls this to suppress
-   * self-write events before fanning out to the controllers.
+   * Decrement-and-report: true iff `fsPath` was a sidecar this store just
+   * wrote via `update`. Each successful `update` increments the counter once;
+   * each call here decrements it (deleting the key at zero). The shared watcher
+   * (extension.ts) calls this to suppress self-write events before fanning out
+   * to the controllers.
    */
   consumeSelfWrite(fsPath: string): boolean {
-    return this.selfWrites.delete(fsPath);
+    const count = this.selfWrites.get(fsPath);
+    if (!count) return false;
+    if (count === 1) {
+      this.selfWrites.delete(fsPath);
+    } else {
+      this.selfWrites.set(fsPath, count - 1);
+    }
+    return true;
   }
 
   /** `.threads/<repo-relative-docPath>.json` (spec §6.3). */
@@ -61,8 +75,12 @@ export class CoauthorStore {
     for (const id of Object.keys(artifact.anchors)) {
       if (!referenced.has(id)) delete artifact.anchors[id];
     }
-    this.selfWrites.add(this.sidecarPath(docPath));
     this.save(docPath, artifact);
+    // Increment AFTER the synchronous write: fs.writeFileSync completes before
+    // this line executes, and watcher events are delivered async, so marking
+    // post-write is race-free for suppression purposes.
+    const p = this.sidecarPath(docPath);
+    this.selfWrites.set(p, (this.selfWrites.get(p) ?? 0) + 1);
     return artifact;
   }
 }

test/store.test.ts

@@ -88,4 +88,22 @@ describe("CoauthorStore", () => {
     });
     expect(Object.keys(store.load("d.md")!.anchors)).toEqual([]);
   });
+
+  it("consumeSelfWrite counts multiple writes to the same sidecar (double-save suppression)", () => {
+    const store = new CoauthorStore(root);
+    store.update("d.md", (a) => {
+      a.anchors["a_t"] = { fingerprint: { text: "t", before: "", after: "", lineHint: 0 } };
+      a.threads.push({ id: "t1", anchorId: "a_t", status: "open", messages: [] });
+    });
+    store.update("d.md", (a) => {
+      a.attributions.push({
+        id: "at1", anchorId: "a_t", author: { kind: "human", id: "ben" },
+        createdAt: "2026-06-10T00:00:00.000Z", updatedAt: "2026-06-10T00:00:00.000Z",
+      });
+    });
+    const p = store.sidecarPath("d.md");
+    expect(store.consumeSelfWrite(p)).toBe(true);
+    expect(store.consumeSelfWrite(p)).toBe(true);
+    expect(store.consumeSelfWrite(p)).toBe(false);
+  });
 });