diff --git a/harness/tests/contract.spec.js b/harness/tests/contract.spec.js
index 906a0455..cb8d816b 100644
--- a/harness/tests/contract.spec.js
+++ b/harness/tests/contract.spec.js
@@ -9,6 +9,19 @@ import { test, expect } from "@playwright/test";
 // the same with the handshake window).
 import { NOTICE_KEY } from "../../web/shell.js";
 
+/** Every string the page posts to its worker, kept on `window.__posted`. */
+function recordPosts() {
+  window.__posted = [];
+  const post = Worker.prototype.postMessage;
+  Worker.prototype.postMessage = function (message, ...rest) {
+    window.__posted.push(String(message));
+    return post.call(this, message, ...rest);
+  };
+}
+
+const setCells = (page) =>
+  page.evaluate(() => window.__posted.filter((m) => m.includes("SetCell")).length);
+
 async function openApp(page) {
   await page.goto("/app/index.html");
   await expect(page.locator("#grid table")).toBeVisible({ timeout: 20_000 });
@@ -320,6 +333,76 @@ test.describe("a pointer event reaches the client and its answer is painted", ()
     await expect.poll(writes).toBe(1);
   });
 
+  // improvise-jibp. The page reports its first edit, so retyping the seed over
+  // the selection is a write, not an untouched editor.
+  test("a mouse editor typed back to its own seed still writes", async ({ page }) => {
+    await page.addInitScript(recordPosts);
+    await openApp(page);
+    const cells = page.locator("#grid tbody td");
+    await cells.nth(4).click();
+    const input = cells.nth(4).locator("input");
+    await expect(input).toHaveCount(1);
+    const seed = await input.inputValue();
+    expect(seed, "the fixture cell has no seed to retype").not.toBe("");
+    await page.keyboard.type(seed);
+    await expect(input).toHaveValue(seed);
+    await page.keyboard.press("Enter");
+    await expect.poll(() => setCells(page)).toBe(1);
+  });
+
+  // improvise-ugj4. A frame that lands while an editor is open changes the
+  // cache but not the paint; the next editor must open on what it captured.
+  test("an editor opened after an unpainted write shows and commits what it captured", async ({
+    page,
+  }) => {
+    await page.addInitScript(recordPosts);
+    await page.addInitScript(() => {
+      window.__frames = [];
+      const add = Worker.prototype.addEventListener;
+      Worker.prototype.addEventListener = function (type, listener, ...rest) {
+        if (type !== "message") return add.call(this, type, listener, ...rest);
+        window.__deliver = (data) => listener.call(this, new MessageEvent("message", { data }));
+        const recorded = (event) => {
+          if (typeof event.data === "string") window.__frames.push(event.data);
+          return listener.call(this, event);
+        };
+        return add.call(this, type, recorded, ...rest);
+      };
+    });
+    await openApp(page);
+    const cells = page.locator("#grid tbody td");
+    const target = cells.nth(4);
+    const where = await target.evaluate((td) => [Number(td.dataset.row), Number(td.dataset.col)]);
+
+    await cells.nth(0).click();
+    await expect(cells.nth(0).locator("input")).toHaveCount(1);
+    // Another client's write to cell 4, delivered while cell 0's editor is open.
+    await page.evaluate(([row, col]) => {
+      let latest = null;
+      const walk = (node) => {
+        if (Array.isArray(node)) node.forEach(walk);
+        else if (node && typeof node === "object") {
+          for (const [key, value] of Object.entries(node)) {
+            if (key === "Cells" && Array.isArray(value)) {
+              for (const [[r, c], cell] of value) if (r === row && c === col) latest = cell;
+            } else walk(value);
+          }
+        }
+      };
+      window.__frames.forEach((f) => walk(JSON.parse(f)));
+      const moved = { ...latest, text: "777", edit_text: "777", value: { Number: 777 } };
+      window.__deliver(JSON.stringify({ Commands: [{ Project: { Grid: { Cells: [[[row, col], moved]] } } }] }));
+    }, where);
+
+    await target.click();
+    const input = target.locator("input");
+    await expect(input).toHaveCount(1);
+    await expect(input, "the editor opened on the stale paint").toHaveValue("777");
+    await page.keyboard.press("Enter");
+    await page.waitForTimeout(300);
+    expect(await setCells(page), "an untouched editor wrote the stale text").toBe(0);
+  });
+
   // improvise-b8ot moved these five surfaces onto one handler per stable root.
   // The three tests below are the properties a naive delegation loses, each of
   // which is silent: the page still paints, and only the pointer stops working.