diff --git a/.github/workflows/call-e2e-all-tests.yml b/.github/workflows/call-e2e-all-tests.yml
index 4260ffea4bb..d1e734362dc 100644
--- a/.github/workflows/call-e2e-all-tests.yml
+++ b/.github/workflows/call-e2e-all-tests.yml
@@ -154,6 +154,19 @@ jobs:
       browser: ${{ matrix.browser }}
       editor-mode: 'rich-text-with-collab'
 
+  collab-v2-linux:
+    needs: [build-ubuntu]
+    strategy:
+      matrix:
+        node-version: [24.x]
+        browser: ['chromium', 'firefox']
+    uses: ./.github/workflows/call-e2e-test.yml
+    with:
+      os: 'ubuntu-latest'
+      node-version: ${{ matrix.node-version }}
+      browser: ${{ matrix.browser }}
+      editor-mode: 'rich-text-with-collab-v2'
+
   collab-windows:
     needs: [build-windows]
     strategy:
@@ -198,19 +211,3 @@ jobs:
       node-version: ${{ matrix.node-version }}
       browser: ${{ matrix.browser }}
       editor-mode: ${{ matrix.editor-mode }}
-  flaky:
-    # There aren't currently any flaky tests
-    if: false
-    needs: [build-ubuntu]
-    strategy:
-      matrix:
-        node-version: [24.x]
-        browser: ['chromium', 'firefox']
-        editor-mode: ['rich-text', 'plain-text', 'rich-text-with-collab']
-    uses: ./.github/workflows/call-e2e-test.yml
-    with:
-      os: 'ubuntu-latest'
-      flaky: true
-      node-version: ${{ matrix.node-version }}
-      browser: ${{ matrix.browser }}
-      editor-mode: ${{ matrix.editor-mode }}
diff --git a/.github/workflows/call-e2e-test.yml b/.github/workflows/call-e2e-test.yml
index 156f4ba382d..7ce9d8d4105 100644
--- a/.github/workflows/call-e2e-test.yml
+++ b/.github/workflows/call-e2e-test.yml
@@ -9,7 +9,6 @@ on:
       browser: {required: true, type: string}
       editor-mode: {required: true, type: string}
       prod: {required: false, type: boolean}
-      flaky: {required: false, type: boolean} # Defaults to false: dont run flaky
       fail-on-cache-miss: {required: false, type: boolean, default: true}
 
 permissions: {}
@@ -17,7 +16,6 @@ permissions: {}
 jobs:
   e2e-test:
     runs-on: ${{ inputs.os }}
-    continue-on-error: ${{ inputs.flaky }}
     if: (inputs.browser != 'webkit' || inputs.os == 'macos-latest')
     env:
       CI: true
@@ -39,19 +37,19 @@ jobs:
           node-version: ${{ inputs.node-version }}
           fail-on-cache-miss: ${{ inputs.fail-on-cache-miss }}
       - name: Run tests
-        if: inputs.editor-mode != 'rich-text-with-collab'
-        run: pnpm run test-e2e-${{ inputs.prod && 'prod-' || '' }}${{ inputs.browser }} ${{ inputs.flaky && '--grep' || '--grep-invert' }} "@flaky"${{ inputs.flaky && ' --pass-with-no-tests' || '' }}
+        if: ${{ !startsWith(inputs.editor-mode, 'rich-text-with-collab') }}
+        run: pnpm run test-e2e-${{ inputs.prod && 'prod-' || '' }}${{ inputs.browser }}
       - name: Run collab tests
-        if: inputs.editor-mode == 'rich-text-with-collab'
+        if: ${{ startsWith(inputs.editor-mode, 'rich-text-with-collab') }}
         shell: bash
         run: |
           pnpm exec concurrently -k -s first \
             "pnpm run collab" \
-            "pnpm run test-e2e-collab-${{ inputs.prod && 'prod-' || '' }}${{ inputs.browser }} ${{ inputs.flaky && '--grep' || '--grep-invert' }} @flaky${{ inputs.flaky && ' --pass-with-no-tests' || '' }}"
+            "pnpm run test-e2e-collab-${{ inputs.editor-mode == 'rich-text-with-collab-v2' && 'v2-' || '' }}${{ inputs.prod && 'prod-' || '' }}${{ inputs.browser }}"
       - name: Upload Artifacts
         if: failure()
         uses: actions/upload-artifact@v7
         with:
-          name: Test Results ${{ inputs.os }}-${{ inputs.browser }}-${{ inputs.editor-mode }}-${{ inputs.prod && 'prod' || 'dev' }}-${{ inputs.node-version }}-${{ inputs.flaky && 'flaky' || ''}}-${{ github.sha }}-${{ github.run_id }}-${{ github.run_attempt }}
+          name: Test Results ${{ inputs.os }}-${{ inputs.browser }}-${{ inputs.editor-mode }}-${{ inputs.prod && 'prod' || 'dev' }}-${{ inputs.node-version }}-${{ github.sha }}-${{ github.run_id }}-${{ github.run_attempt }}
           path: ${{ env.test_results_path }}
           retention-days: 7
diff --git a/package.json b/package.json
index 73d43c125a6..366eb64f66c 100644
--- a/package.json
+++ b/package.json
@@ -62,14 +62,14 @@
     "test-e2e-collab-v2-webkit": "cross-env E2E_BROWSER=webkit E2E_EDITOR_MODE=rich-text-with-collab-v2 playwright test --project=\"webkit\"",
     "test-e2e-prod-chromium": "cross-env E2E_BROWSER=chromium E2E_PORT=4000 playwright test --project=\"chromium\"",
     "test-e2e-collab-prod-chromium": "cross-env E2E_BROWSER=chromium E2E_PORT=4000 E2E_EDITOR_MODE=rich-text-with-collab playwright test --project=\"chromium\"",
-    "test-e2e-ci-chromium": "pnpm run prepare-ci && cross-env E2E_PORT=4000 pnpm run test-e2e-chromium --grep-invert \"@flaky\"",
-    "test-e2e-ci-firefox": "pnpm run prepare-ci && cross-env E2E_PORT=4000 pnpm run test-e2e-firefox --grep-invert \"@flaky\"",
-    "test-e2e-ci-webkit": "pnpm run prepare-ci && cross-env E2E_PORT=4000 pnpm run test-e2e-webkit --grep-invert \"@flaky\"",
-    "test-e2e-collab-ci-chromium": "pnpm run prepare-ci && cross-env E2E_PORT=4000 concurrently -k -s \"first\" \"pnpm run collab\" -P \"pnpm run test-e2e-collab-chromium --grep-invert '@flaky' {@}\"",
-    "test-e2e-collab-ci-firefox": "pnpm run prepare-ci && cross-env E2E_PORT=4000 concurrently -k -s \"first\" \"pnpm run collab\" -P \"pnpm run test-e2e-collab-firefox --grep-invert '@flaky' {@}\"",
-    "test-e2e-collab-ci-webkit": "pnpm run prepare-ci && cross-env E2E_PORT=4000 concurrently -k -s \"first\" \"pnpm run collab\" -P \"pnpm run test-e2e-collab-webkit --grep-invert '@flaky' {@}\"",
-    "test-e2e-prod-ci-chromium": "pnpm run prepare-ci-prod && cross-env E2E_PORT=4000 pnpm run test-e2e-prod-chromium --grep-invert \"@flaky\"",
-    "test-e2e-collab-prod-ci-chromium": "pnpm run prepare-ci-prod && cross-env E2E_PORT=4000 concurrently -k -s \"first\" \"pnpm run collab\" -P \"pnpm run test-e2e-collab-prod-chromium --grep-invert '@flaky' {@}\"",
+    "test-e2e-ci-chromium": "pnpm run prepare-ci && cross-env E2E_PORT=4000 pnpm run test-e2e-chromium",
+    "test-e2e-ci-firefox": "pnpm run prepare-ci && cross-env E2E_PORT=4000 pnpm run test-e2e-firefox",
+    "test-e2e-ci-webkit": "pnpm run prepare-ci && cross-env E2E_PORT=4000 pnpm run test-e2e-webkit",
+    "test-e2e-collab-ci-chromium": "pnpm run prepare-ci && cross-env E2E_PORT=4000 concurrently -k -s \"first\" \"pnpm run collab\" -P \"pnpm run test-e2e-collab-chromium {@}\"",
+    "test-e2e-collab-ci-firefox": "pnpm run prepare-ci && cross-env E2E_PORT=4000 concurrently -k -s \"first\" \"pnpm run collab\" -P \"pnpm run test-e2e-collab-firefox {@}\"",
+    "test-e2e-collab-ci-webkit": "pnpm run prepare-ci && cross-env E2E_PORT=4000 concurrently -k -s \"first\" \"pnpm run collab\" -P \"pnpm run test-e2e-collab-webkit {@}\"",
+    "test-e2e-prod-ci-chromium": "pnpm run prepare-ci-prod && cross-env E2E_PORT=4000 pnpm run test-e2e-prod-chromium",
+    "test-e2e-collab-prod-ci-chromium": "pnpm run prepare-ci-prod && cross-env E2E_PORT=4000 concurrently -k -s \"first\" \"pnpm run collab\" -P \"pnpm run test-e2e-collab-prod-chromium {@}\"",
     "debug-run-all": "npm-run-all 'debug-test-e2e-* -- {1}' --",
     "run-all": "npm-run-all 'test-e2e-* -- {1}' --",
     "debug-test-e2e": "cross-env playwright test --debug",
diff --git a/packages/lexical-playground/__tests__/e2e/ClearFormatting.spec.mjs b/packages/lexical-playground/__tests__/e2e/ClearFormatting.spec.mjs
index 89815224874..8023c9c47c6 100644
--- a/packages/lexical-playground/__tests__/e2e/ClearFormatting.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/ClearFormatting.spec.mjs
@@ -28,7 +28,7 @@ import {
   selectFromBackgroundColorPicker,
   selectFromColorPicker,
   test,
-  waitForSelector,
+  waitForTypeaheadMenuOption,
 } from '../utils/index.mjs';
 
 test.describe('Clear All Formatting', () => {
@@ -131,14 +131,9 @@ test.describe('Clear All Formatting', () => {
 
     await page.keyboard.type('@Luke');
 
-    // Wait until "Luke Skywalker" is the *highlighted* option, not merely
-    // present: while "@Luke" is still being typed, the partial query "@Lu"
-    // also matches "Agent Kallus" (kal**lu**s), which sorts earlier in the
-    // list and is highlighted first, so pressing Enter too early selects it.
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li[aria-selected="true"]:has-text("Luke Skywalker")',
-    );
+    // Wait until "Luke Skywalker" is the *highlighted* option before pressing
+    // Enter; see waitForTypeaheadMenuOption for why merely-present is racy.
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
     await assertHTML(
       page,
       html`
diff --git a/packages/lexical-playground/__tests__/e2e/CodeActionMenu.spec.mjs b/packages/lexical-playground/__tests__/e2e/CodeActionMenu.spec.mjs
index 19f9480854f..c7563abdf8f 100644
--- a/packages/lexical-playground/__tests__/e2e/CodeActionMenu.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/CodeActionMenu.spec.mjs
@@ -208,7 +208,13 @@ test.describe('CodeActionMenu', () => {
     await mouseMoveToSelector(page, 'code.PlaygroundEditorTheme__code');
     await click(page, 'button[aria-label=prettier]');
 
-    await page.waitForTimeout(3000);
+    // Prettier loads and formats asynchronously; wait for the reformatted
+    // result instead of a fixed timeout. Formatting turns the single input
+    // line into multiple lines, so a <br> inside the code block is a reliable
+    // "prettier finished" signal (attached, not visible: <br> has no box).
+    await waitForSelector(page, 'code.PlaygroundEditorTheme__code br', {
+      state: 'attached',
+    });
 
     await assertHTML(
       page,
@@ -254,7 +260,9 @@ test.describe('CodeActionMenu', () => {
     await mouseMoveToSelector(page, 'code.PlaygroundEditorTheme__code');
     await click(page, 'button[aria-label=prettier]');
 
-    await page.waitForTimeout(3000);
+    // Prettier reports invalid syntax asynchronously; wait for the error badge
+    // to appear instead of a fixed timeout (the assertions below do not retry).
+    await waitForSelector(page, 'i.format.prettier-error');
 
     expect(await page.$('i.format.prettier-error')).toBeTruthy();
 
diff --git a/packages/lexical-playground/__tests__/e2e/Collaboration.spec.mjs b/packages/lexical-playground/__tests__/e2e/Collaboration.spec.mjs
index 8fb5c12ed7c..ee7c4e0bed2 100644
--- a/packages/lexical-playground/__tests__/e2e/Collaboration.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/Collaboration.spec.mjs
@@ -10,18 +10,20 @@ import {expect} from '@playwright/test';
 
 import {
   moveLeft,
+  moveToLineBeginning,
+  moveToLineEnd,
   selectCharacters,
   toggleBold,
   undo,
 } from '../keyboardShortcuts/index.mjs';
 import {
+  advanceHistoryClock,
   assertHTML,
   assertSelection,
   click,
   focusEditor,
   html,
   initialize,
-  sleep,
   test,
 } from '../utils/index.mjs';
 
@@ -46,7 +48,7 @@ test.describe('Collaboration', () => {
     await page.keyboard.press('Enter');
     await page.keyboard.press('Enter');
     await page.keyboard.type('world');
-    await sleep(1050); // default merge interval is 1000, add 50ms as overhead due to CI latency.
+    await advanceHistoryClock(page);
     await page.keyboard.press('ArrowUp');
     await page.keyboard.type('hello world again');
 
@@ -229,17 +231,20 @@ test.describe('Collaboration', () => {
     await focusEditor(page);
     await page.keyboard.type('Line 1');
     await page.keyboard.press('Enter');
-    await sleep(1050); // default merge interval is 1000, add 50ms as overhead due to CI latency.
+    await advanceHistoryClock(page);
     await page.keyboard.type('This is a test. ');
 
-    // Right collaborator types at the end of paragraph 2
-    await sleep(1050);
-    await page
-      .frameLocator('iframe[name="right"]')
-      .locator('[data-lexical-editor="true"]')
-      .focus();
-    await page.keyboard.press('ArrowDown'); // Move caret to end of paragraph 2
-    await page.keyboard.press('ArrowDown');
+    // Right collaborator types at the end of paragraph 2. Click into that
+    // paragraph to place the caret — a real remote user positions the cursor
+    // with a click — then move to the line end. Relying on a default caret
+    // position + ArrowDown is fragile: once content has synced in, the idle
+    // frame's selection is not guaranteed to start at the top of the document.
+    const rightFrame = page.frameLocator('iframe[name="right"]');
+    await expect(
+      rightFrame.locator('[data-lexical-editor="true"]'),
+    ).toContainText('This is a test.');
+    await rightFrame.locator('p').nth(1).click();
+    await moveToLineEnd(page);
     await page.keyboard.type('Word');
 
     await assertHTML(
@@ -311,7 +316,7 @@ test.describe('Collaboration', () => {
         </p>
       `,
     );
-    await sleep(1050);
+    await advanceHistoryClock(page);
     await toggleBold(page);
     await page.keyboard.type('bold');
 
@@ -329,12 +334,11 @@ test.describe('Collaboration', () => {
       `,
     );
 
-    // Right collaborator types at the end of the paragraph.
-    await page
-      .frameLocator('iframe[name="right"]')
-      .locator('[data-lexical-editor="true"]')
-      .focus();
-    await page.keyboard.press('ArrowDown', {delay: 50}); // Move caret to end of paragraph
+    // Right collaborator types at the end of the paragraph. Click to place the
+    // caret (real remote user positioning) then move to the line end, rather
+    // than relying on a default caret position + ArrowDown.
+    await page.frameLocator('iframe[name="right"]').locator('p').click();
+    await moveToLineEnd(page);
     await page.keyboard.type('BOLD');
 
     await assertHTML(
@@ -351,9 +355,14 @@ test.describe('Collaboration', () => {
       `,
     );
 
-    // Left collaborator undoes their bold text.
-    await sleep(1050);
-    await page.frameLocator('iframe[name="left"]').getByLabel('Undo').click();
+    // Left collaborator undoes their bold text. The assertHTML above already
+    // confirmed both frames converged, so wait for the undo control to be
+    // actionable instead of sleeping.
+    const undoButton = page
+      .frameLocator('iframe[name="left"]')
+      .getByLabel('Undo');
+    await expect(undoButton).toBeEnabled();
+    await undoButton.click();
 
     // The undo also removed bold the text node from YJS.
     // Check that the dangling text from right user was merged into the preceding text node.
@@ -396,7 +405,7 @@ test.describe('Collaboration', () => {
     await focusEditor(page);
     await page.keyboard.type('normal bold');
 
-    await sleep(1050);
+    await advanceHistoryClock(page);
     await selectCharacters(page, 'left', 'bold'.length);
     await toggleBold(page);
 
@@ -414,12 +423,12 @@ test.describe('Collaboration', () => {
       `,
     );
 
-    // Right collaborator types in the middle of the bold word.
-    await page
-      .frameLocator('iframe[name="right"]')
-      .locator('[data-lexical-editor="true"]')
-      .focus();
-    await page.keyboard.press('ArrowDown', {delay: 50});
+    // Right collaborator types in the middle of the bold word. Click to place
+    // the caret (real remote-user positioning), then step left from the line
+    // end — relying on a default caret position + ArrowDown is fragile because
+    // the idle frame's synced selection isn't guaranteed to start at the top.
+    await page.frameLocator('iframe[name="right"]').locator('p').click();
+    await moveToLineEnd(page);
     await page.keyboard.press('ArrowLeft');
     await page.keyboard.press('ArrowLeft');
     await page.keyboard.type('BOLD');
@@ -481,17 +490,16 @@ test.describe('Collaboration', () => {
       `,
     );
 
-    // Collaboration should still work.
-    await page
-      .frameLocator('iframe[name="right"]')
-      .locator('[data-lexical-editor="true"]')
-      .focus();
-    // TODO this is a workaround for Firefox so that the
-    // selection picks up the text format
+    // Collaboration should still work. Click into the paragraph and move to the
+    // line end, rather than relying on a default caret position + ArrowDown.
+    await page.frameLocator('iframe[name="right"]').locator('p').click();
+    await moveToLineEnd(page);
+    // Firefox doesn't carry the bold format to a caret at the very end of the
+    // bold run, so re-enter the run and return so the appended text inherits it.
     if (browserName === 'firefox') {
-      await page.keyboard.press('ArrowLeft', {delay: 50});
+      await page.keyboard.press('ArrowLeft');
+      await page.keyboard.press('ArrowRight');
     }
-    await page.keyboard.press('ArrowDown', {delay: 50});
     await page.keyboard.type(' text');
 
     await assertHTML(
@@ -521,7 +529,7 @@ test.describe('Collaboration', () => {
     await focusEditor(page);
     await page.keyboard.type('Check out the website!');
 
-    await sleep(1050);
+    await advanceHistoryClock(page);
     await page.keyboard.press('ArrowLeft');
     await selectCharacters(page, 'left', 'website'.length);
     await page
@@ -546,12 +554,11 @@ test.describe('Collaboration', () => {
       `,
     );
 
-    // Right collaborator adds some text.
-    await page
-      .frameLocator('iframe[name="right"]')
-      .locator('[data-lexical-editor="true"]')
-      .focus();
-    await page.keyboard.press('ArrowDown', {delay: 50});
+    // Right collaborator adds some text just before the trailing "!". Click to
+    // place the caret (real remote user positioning), move to the line end,
+    // then step left over "!", rather than relying on a default caret position.
+    await page.frameLocator('iframe[name="right"]').locator('p').click();
+    await moveToLineEnd(page);
     await page.keyboard.press('ArrowLeft');
     await page.keyboard.type(' now');
 
@@ -616,12 +623,11 @@ test.describe('Collaboration', () => {
       `,
     );
 
-    // Collaboration should still work.
-    await page
-      .frameLocator('iframe[name="right"]')
-      .locator('[data-lexical-editor="true"]')
-      .focus();
-    await page.keyboard.press('ArrowDown', {delay: 50});
+    // Collaboration should still work. Click into the paragraph and move to the
+    // line end to append after "now!", rather than relying on a default caret
+    // position + ArrowDown.
+    await page.frameLocator('iframe[name="right"]').locator('p').click();
+    await moveToLineEnd(page);
     await page.keyboard.type(' Check it out.');
 
     await assertHTML(
@@ -674,7 +680,7 @@ test.describe('Collaboration', () => {
     );
 
     // Left collaborator deletes A, right deletes B.
-    await sleep(1050);
+    await advanceHistoryClock(page);
     await page.keyboard.press('Delete');
     await assertHTML(
       page,
@@ -689,10 +695,11 @@ test.describe('Collaboration', () => {
         </p>
       `,
     );
-    await page
-      .frameLocator('iframe[name="right"]')
-      .locator('[data-lexical-editor="true"]')
-      .focus();
+    // Right collaborator deletes "B". Click into the paragraph and move to the
+    // line start so forward-Delete removes the leading bold "B", rather than
+    // relying on a default caret position.
+    await page.frameLocator('iframe[name="right"]').locator('p').click();
+    await moveToLineBeginning(page);
     await page.keyboard.press('Delete');
 
     await assertHTML(
diff --git a/packages/lexical-playground/__tests__/e2e/Composition.spec.mjs b/packages/lexical-playground/__tests__/e2e/Composition.spec.mjs
index 5c44a37237d..b326c12db06 100644
--- a/packages/lexical-playground/__tests__/e2e/Composition.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/Composition.spec.mjs
@@ -27,6 +27,7 @@ import {
   keyUpCtrlOrMeta,
   test,
   waitForSelector,
+  waitForTypeaheadMenuOption,
 } from '../utils/index.mjs';
 
 test.use({launchOptions: {slowMo: 50}});
@@ -644,7 +645,7 @@ test.describe('Composition', () => {
       await enableCompositionKeyEvents(page);
 
       await page.keyboard.type('@Luke');
-      await waitForSelector(page, '#typeahead-menu ul li');
+      await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
       await page.keyboard.press('Enter');
 
       await waitForSelector(page, '.mention');
@@ -754,7 +755,7 @@ test.describe('Composition', () => {
       await enableCompositionKeyEvents(page);
 
       await page.keyboard.type('@Luke');
-      await waitForSelector(page, '#typeahead-menu ul li');
+      await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
       await page.keyboard.press('Enter');
 
       await waitForSelector(page, '.mention');
@@ -861,7 +862,7 @@ test.describe('Composition', () => {
       await enableCompositionKeyEvents(page);
 
       await page.keyboard.type('@Luke');
-      await waitForSelector(page, '#typeahead-menu ul li');
+      await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
       await page.keyboard.press('Enter');
 
       const client = await page.context().newCDPSession(page);
@@ -1284,7 +1285,7 @@ test.describe('Composition', () => {
       await enableCompositionKeyEvents(page);
 
       await page.keyboard.type('@Luke');
-      await waitForSelector(page, '#typeahead-menu ul li');
+      await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
 
       const client = await page.context().newCDPSession(page);
 
diff --git a/packages/lexical-playground/__tests__/e2e/File.spec.mjs b/packages/lexical-playground/__tests__/e2e/File.spec.mjs
index 5ee04b6cb3e..224c66d57e5 100644
--- a/packages/lexical-playground/__tests__/e2e/File.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/File.spec.mjs
@@ -15,7 +15,6 @@ import {
   initialize,
   insertUploadImage,
   IS_COLLAB_V2,
-  sleep,
   test,
   waitForSelector,
 } from '../utils/index.mjs';
@@ -100,8 +99,10 @@ test.describe('File', () => {
       fileChooser.setFiles([filePath]);
     });
     await click(page, '.action-button.import');
-    await sleep(200);
 
+    // The import reads and parses the file asynchronously; assertHTML retries
+    // until the imported document replaces the empty editor, so no fixed wait
+    // is needed.
     await assertHTML(page, expectedHtml);
   });
 });
diff --git a/packages/lexical-playground/__tests__/e2e/History.spec.mjs b/packages/lexical-playground/__tests__/e2e/History.spec.mjs
index 3242893b94b..7a7d92efe8c 100644
--- a/packages/lexical-playground/__tests__/e2e/History.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/History.spec.mjs
@@ -14,13 +14,13 @@ import {
   undo,
 } from '../keyboardShortcuts/index.mjs';
 import {
+  advanceHistoryClock,
   assertHTML,
   assertSelection,
   enableCompositionKeyEvents,
   focusEditor,
   html,
   initialize,
-  sleep,
   test,
 } from '../utils/index.mjs';
 
@@ -34,7 +34,7 @@ test.describe('History', () => {
     test.skip(isCollab);
     await page.focus('div[contenteditable="true"]');
     await page.keyboard.type('hello');
-    await sleep(1050); // default merge interval is 1000, add 50ms as overhead due to CI latency.
+    await advanceHistoryClock(page);
     await page.keyboard.type(' world');
     await page.keyboard.press('Enter');
     await page.keyboard.type('hello world again');
@@ -553,11 +553,11 @@ test.describe('History - IME', () => {
       text: 'すし',
     });
 
-    await sleep(1050); // default merge interval is 1000, add 50ms as overhead due to CI latency.
+    await advanceHistoryClock(page);
 
     await page.keyboard.type(' ');
 
-    await sleep(1050);
+    await advanceHistoryClock(page);
 
     // await page.keyboard.imeSetComposition('m', 1, 1);
     await client.send('Input.imeSetComposition', {
@@ -578,7 +578,7 @@ test.describe('History - IME', () => {
       text: 'もj',
     });
 
-    await sleep(1050);
+    await advanceHistoryClock(page);
 
     // await page.keyboard.imeSetComposition('もじ', 2, 2);
     await client.send('Input.imeSetComposition', {
@@ -742,7 +742,7 @@ test.describe('History - IME', () => {
       text: 'a',
     });
 
-    await sleep(1050);
+    await advanceHistoryClock(page);
 
     await client.send('Input.imeSetComposition', {
       selectionStart: 1,
@@ -825,7 +825,7 @@ test.describe('History - IME', () => {
       text: 'a',
     });
 
-    await sleep(1050);
+    await advanceHistoryClock(page);
 
     await client.send('Input.imeSetComposition', {
       selectionStart: 2,
@@ -901,7 +901,7 @@ test.describe('History - IME', () => {
     await client.send('Input.insertText', {
       text: 'ab',
     });
-    await sleep(1050);
+    await advanceHistoryClock(page);
 
     await page.keyboard.down('Shift');
     await moveLeft(page, 1);
diff --git a/packages/lexical-playground/__tests__/e2e/Mentions.spec.mjs b/packages/lexical-playground/__tests__/e2e/Mentions.spec.mjs
index 0769b471a57..f586f590870 100644
--- a/packages/lexical-playground/__tests__/e2e/Mentions.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/Mentions.spec.mjs
@@ -24,6 +24,7 @@ import {
   pasteFromClipboard,
   test,
   waitForSelector,
+  waitForTypeaheadMenuOption,
 } from '../utils/index.mjs';
 
 test.describe('Mentions', () => {
@@ -39,10 +40,7 @@ test.describe('Mentions', () => {
       focusPath: [0, 0, 0],
     });
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
 
     await assertHTML(
       page,
@@ -114,10 +112,7 @@ test.describe('Mentions', () => {
       focusPath: [0, 0, 0],
     });
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
 
     await assertHTML(
       page,
@@ -209,10 +204,7 @@ test.describe('Mentions', () => {
       focusPath: [0, 0, 0],
     });
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
 
     await assertHTML(
       page,
@@ -285,10 +277,7 @@ test.describe('Mentions', () => {
       focusPath: [0, 0, 0],
     });
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
 
     await assertHTML(
       page,
@@ -361,10 +350,7 @@ test.describe('Mentions', () => {
       focusPath: [0, 0, 0],
     });
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
 
     await assertHTML(
       page,
@@ -458,10 +444,7 @@ test.describe('Mentions', () => {
 
     await page.keyboard.type('@Luke');
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
 
     await assertHTML(
       page,
@@ -534,10 +517,7 @@ test.describe('Mentions', () => {
       focusPath: [0, 0, 0],
     });
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
     await page.keyboard.press('Enter');
 
     await waitForSelector(page, '.mention');
@@ -546,10 +526,7 @@ test.describe('Mentions', () => {
 
     await page.keyboard.type('@Luke');
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
     await page.keyboard.press('Enter');
 
     await waitForSelector(page, '.mention:nth-child(1)');
@@ -558,10 +535,7 @@ test.describe('Mentions', () => {
 
     await page.keyboard.type('@Luke');
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
     await page.keyboard.press('Enter');
 
     await waitForSelector(page, '.mention:nth-child(3)');
@@ -570,10 +544,7 @@ test.describe('Mentions', () => {
 
     await page.keyboard.type('@Luke');
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
     await page.keyboard.press('Enter');
 
     await waitForSelector(page, '.mention:nth-child(5)');
@@ -867,10 +838,7 @@ test.describe('Mentions', () => {
       focusPath: [0, 0, 0],
     });
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
     await page.keyboard.press('Enter');
 
     await waitForSelector(page, '.mention');
@@ -947,10 +915,7 @@ test.describe('Mentions', () => {
       focusPath: [0, 0, 0],
     });
 
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
     await page.keyboard.press('Enter');
 
     await waitForSelector(page, '.mention');
diff --git a/packages/lexical-playground/__tests__/e2e/Selection.spec.mjs b/packages/lexical-playground/__tests__/e2e/Selection.spec.mjs
index 88ed8443c8d..e48d340ada5 100644
--- a/packages/lexical-playground/__tests__/e2e/Selection.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/Selection.spec.mjs
@@ -53,6 +53,7 @@ import {
   selectFromFormatDropdown,
   sleep,
   test,
+  waitForSelector,
   YOUTUBE_SAMPLE_URL,
 } from '../utils/index.mjs';
 
@@ -538,7 +539,10 @@ test.describe('Selection', () => {
     await pasteFromClipboard(page, {
       'text/html': `<a href="https://test.com">link</a>`,
     });
-    await sleep(3000);
+    // Paste inserts the link and places the caret after it in a single update,
+    // so wait for the link to be reconciled rather than sleeping a fixed time
+    // before asserting the (non-retrying) selection.
+    await waitForSelector(page, 'a[href="https://test.com"]');
     await assertSelection(page, {
       anchorOffset: 4,
       anchorPath: [0, 1, 0, 0],
diff --git a/packages/lexical-playground/__tests__/e2e/Tables.spec.mjs b/packages/lexical-playground/__tests__/e2e/Tables.spec.mjs
index dd4e9ec276c..6d2d3f504fd 100644
--- a/packages/lexical-playground/__tests__/e2e/Tables.spec.mjs
+++ b/packages/lexical-playground/__tests__/e2e/Tables.spec.mjs
@@ -22,6 +22,7 @@ import {
   undo,
 } from '../keyboardShortcuts/index.mjs';
 import {
+  advanceHistoryClock,
   assertSelection,
   assertTableHTML as assertHTML,
   assertTableSelectionCoordinates,
@@ -165,17 +166,18 @@ test.describe('Tables', () => {
       window.getSelection().setBaseAndExtent(col, 0, col, 0);
     });
 
-    // Allow Lexical to process the selection change.
-    await sleep(50);
-
     // The DOM caret must not be left inside the <col> / <colgroup> region
     // (the reconciler should have written it back to the resolved cell).
-    const domAnchorNodeName = await evaluate(
-      page,
-      () => window.getSelection().anchorNode?.nodeName ?? null,
-    );
-    expect(domAnchorNodeName).not.toBe('COL');
-    expect(domAnchorNodeName).not.toBe('COLGROUP');
+    // Poll for the selectionchange -> reconcile round-trip instead of sleeping
+    // a fixed time, which can be too short under load.
+    await expect
+      .poll(() =>
+        evaluate(
+          page,
+          () => window.getSelection().anchorNode?.nodeName ?? null,
+        ),
+      )
+      .not.toMatch(/^COL(GROUP)?$/);
 
     // Typing should land in the first cell, not extend "last".
     await page.keyboard.type('X');
@@ -7416,10 +7418,10 @@ test.describe('Tables', () => {
       false,
       false,
     );
-    // undo is used so we need to wait for history
-    await sleep(1050);
-
-    await sleep(1050);
+    // undo is used below, so force a new undo group here. Mode-agnostic:
+    // freezes the @lexical/history clock locally, or resets the Yjs
+    // UndoManager capture window in collab.
+    await advanceHistoryClock(page);
 
     await withExclusiveClipboardAccess(async () => {
       const clipboard = await copyToClipboard(page);
diff --git a/packages/lexical-playground/__tests__/regression/379-backspace-with-mentions.spec.mjs b/packages/lexical-playground/__tests__/regression/379-backspace-with-mentions.spec.mjs
index 6ebe258ffb5..b1aced44d87 100644
--- a/packages/lexical-playground/__tests__/regression/379-backspace-with-mentions.spec.mjs
+++ b/packages/lexical-playground/__tests__/regression/379-backspace-with-mentions.spec.mjs
@@ -14,7 +14,7 @@ import {
   html,
   initialize,
   test,
-  waitForSelector,
+  waitForTypeaheadMenuOption,
 } from '../utils/index.mjs';
 
 test.describe('Regression test #379', () => {
@@ -24,10 +24,7 @@ test.describe('Regression test #379', () => {
   }) => {
     await focusEditor(page);
     await page.keyboard.type('@Luke');
-    await waitForSelector(
-      page,
-      '#typeahead-menu ul li:has-text("Luke Skywalker")',
-    );
+    await waitForTypeaheadMenuOption(page, 'Luke Skywalker');
     await page.keyboard.press('Enter');
     await assertHTML(
       page,
diff --git a/packages/lexical-playground/__tests__/utils/index.mjs b/packages/lexical-playground/__tests__/utils/index.mjs
index 9269a892214..02c2362d513 100644
--- a/packages/lexical-playground/__tests__/utils/index.mjs
+++ b/packages/lexical-playground/__tests__/utils/index.mjs
@@ -704,6 +704,67 @@ export async function sleep(delay) {
   await new Promise(resolve => setTimeout(resolve, delay));
 }
 
+/**
+ * Force a new undo group (a "merge boundary") deterministically — a drop-in
+ * replacement for `sleep(mergeWindow + overhead)`. Works in both editor modes
+ * and picks the right mechanism automatically:
+ *
+ * - **Local history** (`@lexical/history`): coalesces consecutive same-type
+ *   edits while `now() < prevChangeTime + delay`. We drive the extension's
+ *   `now` output signal directly — the lever called out in the task — freezing
+ *   it `delay + overheadMs` past its current value. The next edit is then
+ *   guaranteed to exceed the merge window (new boundary), while later edits
+ *   observe a fixed time so genuinely fast edits still coalesce as in
+ *   production. History reads `now` via `peek()`, so reassigning the signal
+ *   neither re-registers history nor disturbs in-progress merge bookkeeping.
+ * - **Collab** (Yjs `UndoManager`, which `@lexical/history` is disabled in
+ *   favor of): the manager coalesces changes within its own `captureTimeout`
+ *   using `Date.now()`, which isn't injectable. Its public `stopCapturing()`
+ *   resets the window (`lastChange = 0`) so the next change starts a fresh
+ *   stack item — the deterministic equivalent of advancing past the window.
+ *   The manager is published on the editor by `useYjsUndoManager`; see
+ *   `Symbol.for('@lexical/yjs/UndoManager')`.
+ *
+ * Both replace wall-clock sleeps, which are slow and, under CI load, flaky: a
+ * timer that fires late can coalesce edits meant to stay separate (or vice
+ * versa).
+ *
+ * @param {import('@playwright/test').Page} page
+ * @param {number} [overheadMs] slack added past the local-history `delay`,
+ *   mirroring the old `sleep(delay + 50)` convention.
+ */
+export async function advanceHistoryClock(page, overheadMs = 50) {
+  await evaluate(
+    page,
+    overhead => {
+      const editor = document.querySelector(
+        '[data-lexical-editor="true"]',
+      ).__lexicalEditor;
+      // Collab: reset the Yjs UndoManager's capture window.
+      const undoManager = editor[Symbol.for('@lexical/yjs/UndoManager')];
+      if (undoManager) {
+        undoManager.stopCapturing();
+        return;
+      }
+      // Local history: freeze `now` past the merge delay.
+      const builder = editor[Symbol.for('@lexical/extension/LexicalBuilder')];
+      const output = builder?.extensionNameMap.get('@lexical/history/History')
+        ?.state?.output;
+      if (output && !output.disabled.value) {
+        const frozen = output.now.peek()() + output.delay.peek() + overhead;
+        output.now.value = () => frozen;
+        return;
+      }
+      throw new Error(
+        'advanceHistoryClock: no active undo mechanism found on the editor ' +
+          '(expected the Yjs UndoManager in collab, or an enabled ' +
+          '@lexical/history extension otherwise)',
+      );
+    },
+    overheadMs,
+  );
+}
+
 // Fair time for the browser to process a newly inserted image
 export async function sleepInsertImage(count = 1) {
   return await sleep(1000 * count);
@@ -730,6 +791,33 @@ export async function waitForSelector(page, selector, options) {
   await getPageOrFrame(page).waitForSelector(selector, options);
 }
 
+/**
+ * Wait until `optionText` is the *highlighted* (aria-selected) option in the
+ * typeahead / mentions menu, so a subsequent `Enter` deterministically commits
+ * it.
+ *
+ * The mentions lookup is asynchronous and incremental: while e.g. "@Luke" is
+ * being typed, the partial query "Lu" also matches options that sort earlier —
+ * the "Lu" results list "Agent Kallus" (kal**lu**s) at index 0 and only list
+ * "Luke Skywalker" at index 2. Those intermediate result sets resolve on their
+ * own timers, so waiting merely for the option *text* to be present and then
+ * pressing Enter (which commits the highlighted index 0) is racy: under load
+ * the Enter can land while an intermediate list is showing and commit the wrong
+ * option. Waiting for the option to be highlighted is deterministic because the
+ * settled list always highlights the intended option at index 0.
+ *
+ * @param {import('@playwright/test').Page} page
+ * @param {string} optionText
+ * @param {Parameters<import('@playwright/test').Page['waitForSelector']>[1]} [options]
+ */
+export async function waitForTypeaheadMenuOption(page, optionText, options) {
+  await waitForSelector(
+    page,
+    `#typeahead-menu ul li[aria-selected="true"]:has-text("${optionText}")`,
+    options,
+  );
+}
+
 export function locate(page, selector) {
   return getPageOrFrame(page).locator(selector);
 }
diff --git a/packages/lexical-playground/scripts/build-space-dot-font.py b/packages/lexical-playground/scripts/build-space-dot-font.py
new file mode 100644
index 00000000000..fe954f256a2
--- /dev/null
+++ b/packages/lexical-playground/scripts/build-space-dot-font.py
@@ -0,0 +1,129 @@
+#!/usr/bin/env -S uv run --script
+#
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+# /// script
+# requires-python = ">=3.11"
+# dependencies = ["fonttools", "brotli"]
+# ///
+
+# Regenerates the inline WOFF2 used by `VisibleNonPrintingExtension` for the
+# space marker. The font has exactly one visible glyph: a round dot (a
+# middot) of diameter 120 units, centered horizontally in the `U+0020`
+# advance and sitting on the lowercase center line of a 1000 UPM em. Embedded
+# as a base64 data URI in `PlaygroundEditorTheme.css` (`@font-face` block,
+# see the comment above the inline `src`). Run this from the repo root with
+# `uv` (auto-installs `fonttools` and `brotli`):
+#
+#     uv run packages/lexical-playground/scripts/build-space-dot-font.py
+#
+# The script prints the WOFF2 byte size and the base64 payload to paste into
+# the `@font-face` `src` URL.
+#
+# Note: WOFF2 byte size and payload may shift slightly across fontTools /
+# brotli versions for the same glyph input — commit the new base64 (and the
+# byte size in the CSS comment) when you regenerate.
+
+import base64
+import math
+import os
+import sys
+
+from fontTools.fontBuilder import FontBuilder
+from fontTools.pens.ttGlyphPen import TTGlyphPen
+from fontTools.ttLib import TTFont
+
+UPM = 1000
+ADVANCE = 260
+DOT_DIAMETER = 120
+# Center the dot in the advance so it sits in the middle of the rendered
+# space instead of hugging the left edge.
+DOT_CX = ADVANCE // 2
+DOT_CY = 350
+# Quadratic segments used to approximate the circle. 8 is visually round at
+# the sizes we render (sub-pixel deviation from a true circle) and still
+# compresses to a tiny WOFF2.
+DOT_SEGMENTS = 8
+
+
+def draw_dot(pen, cx, cy, radius, segments):
+    """Trace a circle as on-curve points joined by quadratic arcs.
+
+    TrueType outlines are quadratic, so each arc uses a single off-curve
+    control point pushed out to ``radius / cos(half-step)`` — the standard
+    quadratic-Bezier circle approximation.
+    """
+    step = 2.0 * math.pi / segments
+    control_radius = radius / math.cos(step / 2.0)
+    pen.moveTo((round(cx + radius), round(cy)))
+    for i in range(segments):
+        mid_angle = (i + 0.5) * step
+        end_angle = (i + 1) * step
+        control = (
+            round(cx + control_radius * math.cos(mid_angle)),
+            round(cy + control_radius * math.sin(mid_angle)),
+        )
+        end = (
+            round(cx + radius * math.cos(end_angle)),
+            round(cy + radius * math.sin(end_angle)),
+        )
+        pen.qCurveTo(control, end)
+    pen.closePath()
+
+
+def main() -> None:
+    fb = FontBuilder(UPM, isTTF=True)
+    fb.setupGlyphOrder([".notdef", "space"])
+    fb.setupCharacterMap({0x0020: "space"})
+
+    pen = TTGlyphPen(None)
+    draw_dot(pen, DOT_CX, DOT_CY, DOT_DIAMETER / 2.0, DOT_SEGMENTS)
+    space_glyph = pen.glyph()
+
+    notdef_glyph = TTGlyphPen(None).glyph()
+
+    fb.setupGlyf({".notdef": notdef_glyph, "space": space_glyph})
+
+    # The left side bearing must match the glyph's xMin. Browsers position the
+    # outline by its advertised lsb, so leaving it at 0 while the dot starts
+    # ~70 units in shoves the dot toward the left edge of the space instead of
+    # centering it. Derive it from the compiled bounds so it always tracks the
+    # geometry above.
+    glyf_table = fb.font["glyf"]
+    glyf_table["space"].recalcBounds(glyf_table)
+    space_lsb = glyf_table["space"].xMin
+    fb.setupHorizontalMetrics({".notdef": (ADVANCE, 0), "space": (ADVANCE, space_lsb)})
+    fb.setupHorizontalHeader(ascent=800, descent=-200)
+    fb.setupOS2(
+        sTypoAscender=800,
+        sTypoDescender=-200,
+        usWinAscent=800,
+        usWinDescent=200,
+        sCapHeight=700,
+        sxHeight=500,
+    )
+    fb.setupNameTable({"familyName": "LexicalSpaceDot", "styleName": "Regular"})
+    fb.setupPost()
+
+    ttf_path = "/tmp/LexicalSpaceDot.ttf"
+    woff2_path = "/tmp/LexicalSpaceDot.woff2"
+    fb.save(ttf_path)
+
+    font = TTFont(ttf_path)
+    font.flavor = "woff2"
+    font.save(woff2_path)
+
+    size = os.path.getsize(woff2_path)
+    with open(woff2_path, "rb") as f:
+        payload = base64.b64encode(f.read()).decode("ascii")
+
+    sys.stdout.write(f"WOFF2 size: {size} bytes\n")
+    sys.stdout.write("Base64 payload (paste into @font-face src):\n")
+    sys.stdout.write(payload + "\n")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/packages/lexical-playground/src/App.tsx b/packages/lexical-playground/src/App.tsx
index 1dee3512298..e1bcf336442 100644
--- a/packages/lexical-playground/src/App.tsx
+++ b/packages/lexical-playground/src/App.tsx
@@ -87,7 +87,7 @@ import {TerseExportExtension} from './plugins/TerseExportExtension';
 import TestRecorderPlugin from './plugins/TestRecorderPlugin';
 import {TwitterExtension} from './plugins/TwitterExtension';
 import TypingPerfPlugin from './plugins/TypingPerfPlugin';
-import {VisibleLineBreakExtension} from './plugins/VisibleLineBreakExtension';
+import {VisibleNonPrintingExtension} from './plugins/VisibleNonPrintingExtension';
 import {YouTubeExtension} from './plugins/YouTubeExtension';
 import Settings from './Settings';
 import PlaygroundEditorTheme from './themes/PlaygroundEditorTheme';
@@ -238,7 +238,7 @@ const AppExtension = defineExtension({
         $defaultShouldInsertAfter(node) || $isCodeNode(node),
     }),
     configExtension(AutocompleteExtension, {disabled: true}),
-    configExtension(VisibleLineBreakExtension, {disabled: true}),
+    configExtension(VisibleNonPrintingExtension, {disabled: true}),
     // DOMImportExtension pipeline — `PlaygroundImportExtension` bundles
     // the shared `CoreImportExtension` baseline, every per-package
     // import extension (rich-text, list, link, table, code, hr), the
diff --git a/packages/lexical-playground/src/Settings.tsx b/packages/lexical-playground/src/Settings.tsx
index 6bfb7be2714..95f7fa13146 100644
--- a/packages/lexical-playground/src/Settings.tsx
+++ b/packages/lexical-playground/src/Settings.tsx
@@ -29,7 +29,7 @@ export default function Settings(): JSX.Element {
       isCharLimit,
       isCharLimitUtf8,
       isAutocomplete,
-      isVisibleLineBreak,
+      isVisibleNonPrinting,
       showTreeView,
       showNestedEditorTreeView,
       showTableOfContents,
@@ -148,9 +148,11 @@ export default function Settings(): JSX.Element {
             text="Autocomplete"
           />
           <Switch
-            onClick={() => setOption('isVisibleLineBreak', !isVisibleLineBreak)}
-            checked={isVisibleLineBreak}
-            text="Visible Line Break"
+            onClick={() =>
+              setOption('isVisibleNonPrinting', !isVisibleNonPrinting)
+            }
+            checked={isVisibleNonPrinting}
+            text="Visible Non-Printing"
           />
           <Switch
             onClick={() => {
diff --git a/packages/lexical-playground/src/appSettings.ts b/packages/lexical-playground/src/appSettings.ts
index 12e4c4f0658..e3829e9d1ba 100644
--- a/packages/lexical-playground/src/appSettings.ts
+++ b/packages/lexical-playground/src/appSettings.ts
@@ -24,7 +24,7 @@ export const DEFAULT_SETTINGS = {
   isCollab: false,
   isMaxLength: false,
   isRichText: true,
-  isVisibleLineBreak: false,
+  isVisibleNonPrinting: false,
   listStrictIndent: false,
   measureTypingPerf: false,
   selectionAlwaysOnDisplay: false,
diff --git a/packages/lexical-playground/src/hooks/useSynchronizeSettings.ts b/packages/lexical-playground/src/hooks/useSynchronizeSettings.ts
index 715bc074fb3..dafe43715bd 100644
--- a/packages/lexical-playground/src/hooks/useSynchronizeSettings.ts
+++ b/packages/lexical-playground/src/hooks/useSynchronizeSettings.ts
@@ -32,7 +32,7 @@ import {AutocompleteExtension} from '../plugins/AutocompleteExtension';
 import {CodeHighlightExtension} from '../plugins/CodeHighlightExtension';
 import {MaxLengthExtension} from '../plugins/MaxLengthPlugin';
 import {SpecialTextExtension} from '../plugins/SpecialTextExtension';
-import {VisibleLineBreakExtension} from '../plugins/VisibleLineBreakExtension';
+import {VisibleNonPrintingExtension} from '../plugins/VisibleNonPrintingExtension';
 
 const DEFAULT_LINK_ATTRIBUTES: LinkAttributes = {
   rel: 'noopener noreferrer',
@@ -86,8 +86,8 @@ export function synchronizeSettingsToSignals(
   batch(() => {
     output(editor, AutocompleteExtension).disabled.value =
       !settings.isAutocomplete;
-    output(editor, VisibleLineBreakExtension).disabled.value =
-      !settings.isVisibleLineBreak;
+    output(editor, VisibleNonPrintingExtension).disabled.value =
+      !settings.isVisibleNonPrinting;
     output(editor, MaxLengthExtension).disabled.value = !settings.isMaxLength;
     const codeHighlight = peerOutput(editor, CodeHighlightExtension);
     if (codeHighlight) {
diff --git a/packages/lexical-playground/src/index.css b/packages/lexical-playground/src/index.css
index dbfc58a016d..33f57eafb01 100644
--- a/packages/lexical-playground/src/index.css
+++ b/packages/lexical-playground/src/index.css
@@ -20,6 +20,9 @@ body {
     BlinkMacSystemFont,
     '.SFNSText-Regular',
     sans-serif;
+  --font-family:
+    system-ui, -apple-system, BlinkMacSystemFont, '.SFNSText-Regular',
+    sans-serif;
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
   background: #eee;
diff --git a/packages/lexical-playground/src/plugins/VisibleLineBreakExtension.ts b/packages/lexical-playground/src/plugins/VisibleLineBreakExtension.ts
deleted file mode 100644
index d622da9c4e0..00000000000
--- a/packages/lexical-playground/src/plugins/VisibleLineBreakExtension.ts
+++ /dev/null
@@ -1,123 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- */
-import {$isCodeNode} from '@lexical/code-core';
-import {effect, namedSignals} from '@lexical/extension';
-import {
-  $setRenderContextValue,
-  createRenderState,
-  domOverride,
-  DOMRenderExtension,
-} from '@lexical/html';
-import {
-  configExtension,
-  defineExtension,
-  isHTMLElement,
-  LineBreakNode,
-  safeCast,
-} from 'lexical';
-
-/**
- * Worked example for the generalized `getDOMSlot` abstraction — wraps each
- * `LineBreakNode`'s `<br>` in a `<span>` carrying a visible `↵` marker, and
- * exposes the inner `<br>` through `$getDOMSlot` so selection / caret logic
- * targets the canonical content element instead of the wrapper.
- *
- * Demonstrates the extension-driven path for a leaf node category: no
- * `LineBreakNode` subclass required, behaviour attaches via
- * `DOMRenderExtension` configuration.
- *
- * `disabled` toggles the wrap at runtime without recreating the editor. The
- * override is installed conditionally via `disabledForEditor`, so when disabled
- * it is removed from the render pipeline entirely rather than no-oping per
- * node. Flipping the signal mirrors it into the editor render context with
- * `$setRenderContextValue`, which recompiles the render config and recreates
- * the existing `LineBreakNode` DOM through the new config.
- */
-const VISIBLE_LINEBREAK_CLASS = 'visible-linebreak';
-const VISIBLE_LINEBREAK_ATTR = 'data-lexical-visible-linebreak';
-
-export interface VisibleLineBreakConfig {
-  disabled: boolean;
-}
-
-/**
- * Editor render context state mirroring the extension's `disabled` signal.
- */
-export const VisibleLineBreakDisabled = createRenderState(
-  'visibleLineBreakDisabled',
-  () => false,
-);
-
-function $skipForCodeChild(node: LineBreakNode): boolean {
-  // Code blocks convey line structure visually — skip the visible
-  // linebreak wrap anywhere inside a `CodeNode`.
-  for (
-    let ancestor = node.getParent();
-    ancestor !== null;
-    ancestor = ancestor.getParent()
-  ) {
-    if ($isCodeNode(ancestor)) {
-      return true;
-    }
-  }
-  return false;
-}
-
-function hasOurWrap(dom: HTMLElement): boolean {
-  return dom.tagName === 'SPAN' && dom.hasAttribute(VISIBLE_LINEBREAK_ATTR);
-}
-
-export const VisibleLineBreakExtension = defineExtension({
-  build: (editor, config) => namedSignals(config),
-  config: safeCast<VisibleLineBreakConfig>({disabled: false}),
-  dependencies: [
-    configExtension(DOMRenderExtension, {
-      overrides: [
-        domOverride(
-          [LineBreakNode],
-          {
-            $createDOM: (node, $next) => {
-              const inner = $next();
-              if ($skipForCodeChild(node)) {
-                return inner;
-              }
-              const wrapper = document.createElement('span');
-              wrapper.className = VISIBLE_LINEBREAK_CLASS;
-              wrapper.setAttribute(VISIBLE_LINEBREAK_ATTR, 'true');
-              wrapper.appendChild(inner);
-              return wrapper;
-            },
-            $getDOMSlot: (_node, dom, $next) => {
-              const br = dom.querySelector(':scope > br');
-              return isHTMLElement(br) ? $next().withElement(br) : $next();
-            },
-            $updateDOM: (node, _prev, dom, $next) => {
-              const wantsWrap = !$skipForCodeChild(node);
-              if (wantsWrap !== hasOurWrap(dom)) {
-                return true;
-              }
-              return $next();
-            },
-          },
-          {disabledForEditor: ctx => ctx.get(VisibleLineBreakDisabled)},
-        ),
-      ],
-    }),
-  ],
-  name: '@lexical/playground/visible-linebreak',
-  register: (editor, _config, state) => {
-    const stores = state.getOutput();
-    return effect(() => {
-      $setRenderContextValue(
-        VisibleLineBreakDisabled,
-        stores.disabled.value,
-        editor,
-      );
-    });
-  },
-});
diff --git a/packages/lexical-playground/src/plugins/VisibleNonPrintingExtension.ts b/packages/lexical-playground/src/plugins/VisibleNonPrintingExtension.ts
new file mode 100644
index 00000000000..d2a970a1266
--- /dev/null
+++ b/packages/lexical-playground/src/plugins/VisibleNonPrintingExtension.ts
@@ -0,0 +1,236 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+import type {DOMOverrideOptions} from '@lexical/html';
+
+import {$isCodeNode} from '@lexical/code-core';
+import {effect, namedSignals} from '@lexical/extension';
+import {
+  $setRenderContextValue,
+  createRenderState,
+  domOverride,
+  DOMRenderExtension,
+} from '@lexical/html';
+import {ListItemNode} from '@lexical/list';
+import {HeadingNode, QuoteNode} from '@lexical/rich-text';
+import {$canShowPlaceholder} from '@lexical/text';
+import {$findMatchingParent, mergeRegister} from '@lexical/utils';
+import {
+  $isTabNode,
+  configExtension,
+  defineExtension,
+  ElementNode,
+  getStyleObjectFromCSS,
+  isHTMLElement,
+  LineBreakNode,
+  ParagraphNode,
+  safeCast,
+  TabNode,
+  TextNode,
+} from 'lexical';
+
+/**
+ * Surfaces a visible marker for each non-printing character in the editor.
+ * Currently covers:
+ * - `LineBreakNode` (`↵`) — wraps each `<br>` in a `<span>` carrying the
+ *   marker, and exposes the inner `<br>` through `$getDOMSlot` so selection /
+ *   caret logic targets the canonical content element.
+ * - `ParagraphNode` / `HeadingNode` / `ListItemNode` / `QuoteNode` (`¶`) —
+ *   shared `data-lexical-visible-non-printing-block` attribute on the block's
+ *   DOM, visual rendered via CSS `::after`. The marker is `position: absolute`
+ *   and `:has(> br:last-child)` snaps it to `bottom: 0` so a trailing
+ *   placeholder `<br>` (added by `$reconcileElementTerminatingLineBreak` when
+ *   Shift+Enter ends the block) shares the empty line instead of bumping the
+ *   marker onto a new one. The direct-child selector keeps a wrapped
+ *   `LineBreakNode`'s inner `<br>` from accidentally matching.
+ * - `TabNode` (`→`) — `data-` attribute marker rendered via CSS `::before`,
+ *   centered with `position: absolute; transform: translate(-50%, -50%)` so the
+ *   arrow sits in the middle of the tab whitespace rather than at the left
+ *   edge. Indent applied via `INDENT_CONTENT_COMMAND` (Tab on a block-start
+ *   caret) does not create a `TabNode` and is therefore not marked, matching
+ *   Word's "Show formatting marks" behaviour where indent and literal tabs are
+ *   distinct.
+ * - Space (` `, U+0020) (`·`) — an inline WOFF2 with `unicode-range: U+0020`
+ *   remaps only the space glyph to a middle-dot shape, gated by the editor
+ *   root's `data-lexical-visible-non-printing-active` attribute. A
+ *   `TextNode` `$createDOM` / `$updateDOM` override prepends our font in
+ *   front of any inline `style="font-family"` so the toolbar font-family
+ *   selector can't strip the marker via specificity. Zero text-content
+ *   mutation, so IME composition, selection, and caret behaviour stay
+ *   intact.
+ *
+ * Demonstrates the extension-driven path for leaf and block node categories:
+ * no subclassing required, behaviour attaches via `DOMRenderExtension`
+ * configuration.
+ *
+ * `disabled` toggles the markers at runtime without recreating the editor.
+ * The overrides are installed conditionally via `disabledForEditor`, so when
+ * disabled they are removed from the render pipeline entirely rather than
+ * no-oping per node. Flipping the signal mirrors it into the editor render
+ * context with `$setRenderContextValue`, which recompiles the render config
+ * and recreates the existing DOM through the new config. The empty-root
+ * listener is registered inside the `effect` callback so it tears down when
+ * the extension is disabled instead of running forever.
+ */
+const VISIBLE_NON_PRINTING_LINEBREAK_ATTR =
+  'data-lexical-visible-non-printing-linebreak';
+const VISIBLE_NON_PRINTING_BLOCK_ATTR =
+  'data-lexical-visible-non-printing-block';
+const VISIBLE_NON_PRINTING_EMPTY_ROOT_ATTR =
+  'data-lexical-visible-non-printing-empty-root';
+const VISIBLE_NON_PRINTING_ACTIVE_ATTR =
+  'data-lexical-visible-non-printing-active';
+const VISIBLE_NON_PRINTING_TAB_ATTR = 'data-lexical-visible-non-printing-tab';
+
+export interface VisibleNonPrintingConfig {
+  disabled: boolean;
+}
+
+/**
+ * Editor render context state mirroring the extension's `disabled` signal.
+ */
+export const VisibleNonPrintingDisabled = createRenderState(
+  'visibleNonPrintingDisabled',
+  () => false,
+);
+
+function $skipForCodeChild(node: LineBreakNode): boolean {
+  // Code blocks convey line structure visually — skip the visible
+  // linebreak wrap anywhere inside a `CodeNode`.
+  return $findMatchingParent(node, $isCodeNode) !== null;
+}
+
+function hasOurWrap(dom: HTMLElement): boolean {
+  return (
+    dom.tagName === 'SPAN' &&
+    dom.hasAttribute(VISIBLE_NON_PRINTING_LINEBREAK_ATTR)
+  );
+}
+
+const LEXICAL_SPACE_DOT_FONT = "'LexicalSpaceDot'";
+
+const disabledForEditor = {
+  disabledForEditor: ctx => ctx.get(VisibleNonPrintingDisabled),
+} satisfies DOMOverrideOptions;
+
+export const VisibleNonPrintingExtension = defineExtension({
+  build: (editor, config) => namedSignals(config),
+  config: safeCast<VisibleNonPrintingConfig>({disabled: false}),
+  dependencies: [
+    configExtension(DOMRenderExtension, {
+      overrides: [
+        domOverride(
+          [LineBreakNode],
+          {
+            $createDOM: (node, $next) => {
+              const inner = $next();
+              if ($skipForCodeChild(node)) {
+                return inner;
+              }
+              const wrapper = document.createElement('span');
+              wrapper.setAttribute(VISIBLE_NON_PRINTING_LINEBREAK_ATTR, 'true');
+              wrapper.appendChild(inner);
+              return wrapper;
+            },
+            $getDOMSlot: (_node, dom, $next) => {
+              const br = dom.querySelector(':scope > br');
+              return isHTMLElement(br) ? $next().withElement(br) : $next();
+            },
+            $updateDOM: (node, _prev, dom, $next) => {
+              const wantsWrap = !$skipForCodeChild(node);
+              if (wantsWrap !== hasOurWrap(dom)) {
+                return true;
+              }
+              return $next();
+            },
+          },
+          disabledForEditor,
+        ),
+        domOverride<ElementNode>(
+          [ParagraphNode, HeadingNode, ListItemNode, QuoteNode],
+          {
+            $decorateDOM: (node, _prevNode, dom) => {
+              dom.setAttribute(VISIBLE_NON_PRINTING_BLOCK_ATTR, 'true');
+              const nextTextStyle = getStyleObjectFromCSS(node.__textStyle);
+              for (const prop of ['font-size', 'font-weight', 'font-family']) {
+                dom.style.setProperty(
+                  `--text-${prop}`,
+                  nextTextStyle[prop] || null,
+                );
+              }
+            },
+          },
+          disabledForEditor,
+        ),
+        domOverride(
+          [TextNode, TabNode],
+          {
+            $decorateDOM: (node, _prev, dom) => {
+              // TabNode descends from TextNode so we are going to hit this case either way
+              if ($isTabNode(node)) {
+                dom.setAttribute(VISIBLE_NON_PRINTING_TAB_ATTR, 'true');
+                return;
+              }
+              // Prepend our space-dot font in front of any inline `font-family` set on a
+              // TextNode's span (e.g. by the playground's font-family toolbar). The root
+              // rule's `font-family` stack already covers spans without an inline style;
+              // the inline one wins specificity, so we have to apply the override at the
+              // node level. `unicode-range: U+0020` still scopes the substitution to the
+              // space glyph alone, so the user's chosen face renders every other glyph.
+              const inline =
+                dom.style.fontFamily ||
+                getStyleObjectFromCSS(node.__style)['font-family'] ||
+                'var(--font-family)';
+              if (inline.startsWith(LEXICAL_SPACE_DOT_FONT)) {
+                return;
+              }
+              dom.style.fontFamily = `${LEXICAL_SPACE_DOT_FONT}, ${inline}`;
+            },
+          },
+          disabledForEditor,
+        ),
+      ],
+    }),
+  ],
+  name: '@lexical/playground/visible-non-printing',
+  register: (editor, _config, state) => {
+    const stores = state.getOutput();
+    return effect(() => {
+      const isDisabled = stores.disabled.value;
+      $setRenderContextValue(VisibleNonPrintingDisabled, isDisabled, editor);
+      if (isDisabled) {
+        return;
+      }
+      return editor.registerRootListener(nextRoot => {
+        if (nextRoot === null) {
+          return;
+        }
+        nextRoot.setAttribute(VISIBLE_NON_PRINTING_ACTIVE_ATTR, 'true');
+        const syncEmptyRootAttr = () => {
+          const showPlaceholder = editor
+            .getEditorState()
+            .read(() => $canShowPlaceholder(editor.isComposing()));
+          nextRoot.toggleAttribute(
+            VISIBLE_NON_PRINTING_EMPTY_ROOT_ATTR,
+            showPlaceholder,
+          );
+        };
+        syncEmptyRootAttr();
+        // mergeRegister tears down in LIFO order: the attribute removal runs
+        // before the update listener unregister, so `syncEmptyRootAttr` can't
+        // refire on a half-cleaned root between the two cleanups.
+        return mergeRegister(
+          editor.registerUpdateListener(syncEmptyRootAttr),
+          () => {
+            nextRoot.removeAttribute(VISIBLE_NON_PRINTING_ACTIVE_ATTR);
+            nextRoot.removeAttribute(VISIBLE_NON_PRINTING_EMPTY_ROOT_ATTR);
+          },
+        );
+      });
+    });
+  },
+});
diff --git a/packages/lexical-playground/src/themes/PlaygroundEditorTheme.css b/packages/lexical-playground/src/themes/PlaygroundEditorTheme.css
index ab779f1d39b..e25ad977462 100644
--- a/packages/lexical-playground/src/themes/PlaygroundEditorTheme.css
+++ b/packages/lexical-playground/src/themes/PlaygroundEditorTheme.css
@@ -118,6 +118,7 @@
 .PlaygroundEditorTheme__textCode {
   background-color: rgb(240, 242, 245);
   padding: 1px 0.25rem;
+  --font-family: Menlo, Consolas, Monaco, monospace;
   font-family: Menlo, Consolas, Monaco, monospace;
   font-size: 94%;
 }
@@ -164,6 +165,7 @@
 .PlaygroundEditorTheme__code {
   background-color: rgb(240, 242, 245);
   font-family: Menlo, Consolas, Monaco, monospace;
+  --font-family: Menlo, Consolas, Monaco, monospace;
   display: block;
   line-height: 1.53;
   font-size: 13px;
@@ -740,10 +742,73 @@
     min-height: var(--page-height);
   }
 }
-[data-lexical-visible-linebreak]::before {
+[data-lexical-visible-non-printing-linebreak]::before {
   content: '↵';
   color: #999;
   pointer-events: none;
   user-select: none;
   -webkit-user-select: none;
+  position: absolute;
+}
+[data-lexical-visible-non-printing-block] {
+  position: relative;
+}
+[data-lexical-visible-non-printing-block]::after {
+  content: '¶';
+  color: #999;
+  pointer-events: none;
+  user-select: none;
+  -webkit-user-select: none;
+  font-size: var(--text-font-size, inherit);
+  font-weight: var(--text-font-weight, inherit);
+  font-family: var(--text-font-family, inherit);
+  text-decoration: none;
+  position: absolute;
+}
+[data-lexical-visible-non-printing-block]:has(br:only-child) {
+  font-size: var(--text-font-size, inherit);
+  font-weight: var(--text-font-weight, inherit);
+  font-family: var(--text-font-family, inherit);
+}
+[data-lexical-visible-non-printing-block]:has(br:last-child)::after {
+  bottom: 0;
+}
+[data-lexical-visible-non-printing-empty-root]
+  [data-lexical-visible-non-printing-block]::after {
+  content: '\200B';
+}
+[data-lexical-visible-non-printing-tab] {
+  position: relative;
+}
+[data-lexical-visible-non-printing-tab]::before {
+  content: '';
+  position: absolute;
+  left: 8%;
+  right: 8%;
+  top: 50%;
+  height: 8px;
+  transform: translateY(-50%);
+  /* Two-layer composition: fixed-size SVG arrowhead pinned to the right end,
+     plus a 1px stem that stretches across the rest of the tab whitespace.
+     Decouples the arrowhead shape from tab width so heading fonts (large tab
+     widths) and body fonts (small tab widths) both render a sane arrow. */
+  background:
+    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 6 8'%3E%3Cpath d='M0 0 L6 4 L0 8' fill='none' stroke='%23999' stroke-width='1.2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E")
+      no-repeat right center / 6px 8px,
+    linear-gradient(#999, #999) no-repeat left center / calc(100% - 6px) 1px;
+  pointer-events: none;
+  user-select: none;
+  -webkit-user-select: none;
+}
+/* Inline WOFF2 (~308 bytes) whose only glyph is a 120×120 unit square dot
+   centered at (130, 350) in a 1000 UPM space slot — maps U+0020 to a middle
+   dot for the VisibleNonPrintingExtension. Regenerate via
+   packages/lexical-playground/scripts/build-space-dot-font.py (requires
+   fonttools + brotli). */
+@font-face {
+  font-family: 'LexicalSpaceDot';
+  src: url('data:font/woff2;base64,d09GMgABAAAAAAFMAAoAAAAAAqQAAAEFAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAABmAANAo4TwE2AiQDBgsGAAQgBXgHJhsAAiAvCmwbtjU1FiYhthYrpIeZP0WUDdns/1FKf0mxBFuaQjicQUicrhqlCPGg0W2W9y1dXXVcQyQEwQiD/qtPR6qarErVtE5oiiLwZ2DZQ/6H47jBcUQBQcKB0aD7Io/jhLuN+fQIbnfU7qKeyosJRQxw2QbD6OM/+vAFkF96xwANHeu6YF0ZKCUY/zzJAqCBQrCMVUABsvzk9M3G8Xrmm8uz/2E7y9nZyfIO60AQXnvE07/p3n/g+9o3cg8hn1joGggzLUp50HwIACApPKholgU0AACUCwGxhIBmypIuNSMObVbYLDp//JnAb9cc+UrqG6VTjxHgpg2EYiENarkcHCTaCQA=')
+    format('woff2');
+  unicode-range: U+0020;
+  font-display: block;
 }
diff --git a/packages/lexical-react/src/shared/useYjsCollaboration.tsx b/packages/lexical-react/src/shared/useYjsCollaboration.tsx
index 44c6fbe5992..db8cf4a97bc 100644
--- a/packages/lexical-react/src/shared/useYjsCollaboration.tsx
+++ b/packages/lexical-react/src/shared/useYjsCollaboration.tsx
@@ -58,6 +58,16 @@ import {InitialEditorStateType} from '../LexicalComposer';
 
 export type CursorsContainerRef = React.RefObject<HTMLElement | null>;
 
+/**
+ * Well-known key under which the active Yjs {@link UndoManager} is published on
+ * the editor instance (mirroring how `@lexical/extension` attaches its builder
+ * via a `Symbol.for` key). Collab disables `@lexical/history`, so this is the
+ * handle tooling and e2e tests use to force a deterministic undo boundary via
+ * `editor[COLLAB_UNDO_MANAGER]?.stopCapturing()` instead of waiting out the
+ * UndoManager capture timeout.
+ */
+const COLLAB_UNDO_MANAGER = Symbol.for('@lexical/yjs/UndoManager');
+
 type OnYjsTreeChanges = (
   // The below `any` type is taken directly from the vendor types for YJS.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
@@ -560,6 +570,20 @@ function useYjsUndoManager(editor: LexicalEditor, undoManager: UndoManager) {
       ),
     );
   });
+  // Publish the UndoManager on the editor (see COLLAB_UNDO_MANAGER) so tooling
+  // and e2e tests can reach it; remove it again when it changes or unmounts.
+  useEffect(() => {
+    const withManager = editor as LexicalEditor &
+      Record<symbol, UndoManager | undefined>;
+    // eslint-disable-next-line react-hooks/immutability
+    withManager[COLLAB_UNDO_MANAGER] = undoManager;
+    return () => {
+      if (withManager[COLLAB_UNDO_MANAGER] === undoManager) {
+        delete withManager[COLLAB_UNDO_MANAGER];
+      }
+    };
+  }, [editor, undoManager]);
+
   const clearHistory = useCallback(() => {
     undoManager.clear();
   }, [undoManager]);
diff --git a/packages/lexical-website/docs/serialization/dom-render.md b/packages/lexical-website/docs/serialization/dom-render.md
index 3f2679f5809..a138a0457a7 100644
--- a/packages/lexical-website/docs/serialization/dom-render.md
+++ b/packages/lexical-website/docs/serialization/dom-render.md
@@ -450,7 +450,7 @@ configExtension(DOMRenderExtension, {
       {
         $createDOM(node, $next) {
           const wrapper = document.createElement('span');
-          wrapper.className = 'visible-linebreak';
+          wrapper.className = 'visible-non-printing-linebreak';
           wrapper.appendChild($next());
           return wrapper;
         },