diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/components/ShuffledResponsePool/index.vue b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/components/ShuffledResponsePool/index.vue
index 2153493a89..3621797039 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/components/ShuffledResponsePool/index.vue
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/components/ShuffledResponsePool/index.vue
@@ -43,8 +43,8 @@
   import isEqual from 'lodash/isEqual';
   import shuffle from 'lodash/shuffle';
   import { themeTokens, themePalette } from 'kolibri-design-system/lib/styles/theme';
-  import { richTextComparisonKey } from '../../utils/richText';
   import TipTapEditor from 'shared/views/TipTapEditor/TipTapEditor/TipTapEditor';
+  import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
   import EditorImageProcessor from 'shared/views/TipTapEditor/TipTapEditor/services/imageService';
 
   export default {
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/Editor.vue b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/Editor.vue
index db539c994c..174e989a49 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/Editor.vue
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/Editor.vue
@@ -248,8 +248,9 @@
   import ClickableRegion from '../../components/ClickableRegion/index.vue';
   import ShuffledResponsePool from '../../components/ShuffledResponsePool/index.vue';
   import EditableChipList from '../../components/EditableChipList/index.vue';
-  import { hasRichTextContent, richTextComparisonKey } from '../../utils/richText';
+  import { hasRichTextContent } from '../../utils/richText';
   import TipTapEditor from 'shared/views/TipTapEditor/TipTapEditor/TipTapEditor';
+  import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
   import EditorImageProcessor from 'shared/views/TipTapEditor/TipTapEditor/services/imageService';
 
   /** Which card currently holds the open TipTap editor. */
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/__tests__/parse.spec.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/__tests__/parse.spec.js
index c32e3ab262..78fa53bba0 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/__tests__/parse.spec.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/__tests__/parse.spec.js
@@ -13,6 +13,9 @@ const contentsOf = pairs => pairs.map(pair => pair.map(choice => choice.content)
 
 const SCHEMA = { baseType: BaseType.PAIR, cardinality: Cardinality.MULTIPLE };
 
+const SOLVE_X2 = '<p>Solve <span data-latex="x^2"></span> for x</p>';
+const SOLVE_Y3 = '<p>Solve <span data-latex="y^3"></span> for x</p>';
+
 const parseXmlString = xml => parseXML(xml).documentElement;
 
 describe('parse()', () => {
@@ -430,6 +433,21 @@ describe('parse → buildXML → parse round-trip', () => {
     ]);
   });
 
+  it('preserves two choices with the same text but different formulas', () => {
+    const state = {
+      responseIdentifier: 'RESPONSE',
+      prompt: '',
+      pairs: [
+        [
+          { id: 'choice_aaa11111', content: SOLVE_X2 },
+          { id: 'choice_bbb22222', content: SOLVE_Y3 },
+        ],
+      ],
+      distractors: [],
+    };
+    expect(contentsOf(roundTrip(state).pairs)).toEqual([[SOLVE_X2, SOLVE_Y3]]);
+  });
+
   it('preserves the default state as one pair of two blank choices', () => {
     const reparsed = roundTrip(parse('', []));
     expect(contentsOf(reparsed.pairs)).toEqual([['', '']]);
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/__tests__/validation.spec.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/__tests__/validation.spec.js
index 433b0639a5..f14264cdd9 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/__tests__/validation.spec.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/__tests__/validation.spec.js
@@ -1,5 +1,6 @@
 import { validateAssociateInteraction } from '../validation';
 import { ValidationError } from '../../../constants';
+import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
 
 function makeState(overrides = {}) {
   return {
@@ -136,7 +137,7 @@ describe('validateAssociateInteraction()', () => {
       const errors = validateAssociateInteraction(state);
       expect(errors).toContainEqual({
         code: ValidationError.DUPLICATE_DISTRACTOR_CONTENT,
-        text: 'Lysander',
+        text: richTextComparisonKey('Lysander'),
       });
       expect(
         errors.filter(e => e.code === ValidationError.DUPLICATE_DISTRACTOR_CONTENT),
@@ -147,7 +148,7 @@ describe('validateAssociateInteraction()', () => {
       const state = makeState({ distractors: [{ id: 'choice_eee55555', content: 'Antonio' }] });
       expect(validateAssociateInteraction(state)).toContainEqual({
         code: ValidationError.DUPLICATE_DISTRACTOR_CONTENT,
-        text: 'Antonio',
+        text: richTextComparisonKey('Antonio'),
       });
     });
 
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/parse.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/parse.js
index 908db6eb14..21d782ea8b 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/parse.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/parse.js
@@ -4,8 +4,9 @@ import { QTIDeclaration } from '../../serialization/qti/QTIDeclaration';
 import { buildXmlNode, getContentHTML, getPromptHTML, parseXML } from '../../serialization/xml';
 import CorrectResponse from '../../serialization/qti/declarations/correctResponse';
 import { generateRandomSlug } from '../../utils/generateRandomSlug';
-import { hasRichTextContent, richTextComparisonKey } from '../../utils/richText';
+import { hasRichTextContent } from '../../utils/richText';
 import { RESPONSE_IDENTIFIER } from '../../constants';
+import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
 
 const serializer = new XMLSerializer();
 
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/validation.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/validation.js
index 7a728d9cf4..d6628e9f94 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/validation.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/associate/validation.js
@@ -1,6 +1,7 @@
 import flatten from 'lodash/flatten';
 import { ValidationError } from '../../constants';
-import { hasRichTextContent, richTextComparisonKey } from '../../utils/richText';
+import { hasRichTextContent } from '../../utils/richText';
+import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
 
 /**
  * Validate AssociateState → ValidationError[].
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/choice/__tests__/validation.spec.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/choice/__tests__/validation.spec.js
index 9f6e8224e2..23d9d2a868 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/choice/__tests__/validation.spec.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/choice/__tests__/validation.spec.js
@@ -132,6 +132,20 @@ describe('validate()', () => {
         ValidationError.DUPLICATE_CHOICE_CONTENT,
       );
     });
+
+    it.each([
+      ['a formula', '<span data-latex="x^2"></span>', '<span data-latex="y^3"></span>'],
+      ['an image', '<img src="abc123.png"/>', '<img src="def456.png"/>'],
+      ['a script', '<sup>2</sup>', '<sub>2</sub>'],
+    ])('does not flag choices with the same text but %s that differs', (_, first, second) => {
+      const state = makeState({
+        choices: [
+          makeAnswer({ id: 'a', content: `<p>Solve ${first} for x</p>`, correct: true }),
+          makeAnswer({ id: 'b', content: `<p>Solve ${second} for x</p>`, correct: false }),
+        ],
+      });
+      expect(validate(state, QuestionType.SINGLE_SELECT)).toEqual([]);
+    });
   });
 
   describe('EMPTY_CHOICE_CONTENT', () => {
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/choice/validation.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/choice/validation.js
index 91a09a21c0..e95154b237 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/choice/validation.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/choice/validation.js
@@ -1,5 +1,6 @@
 import { QuestionType, ValidationError } from '../../constants';
-import { hasRichTextContent, richTextComparisonKey } from '../../utils/richText';
+import { hasRichTextContent } from '../../utils/richText';
+import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
 
 /**
  * Validate ChoiceState → ValidationError[].
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/descriptors.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/descriptors.js
index 395196005d..b7aa3360d9 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/descriptors.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/descriptors.js
@@ -9,8 +9,9 @@ import { inlineChoiceInteractionDescriptor } from './inlineChoice/Descriptor';
 /**
  * Every interaction's descriptor: matching, parsing, building and validating XML.
  *
- * This module imports `Descriptor.js` files only so that headless validation can be done withou
- * the bundle size cost of the editors.
+ * This module imports `Descriptor.js` files only so that headless validation does not load the
+ * interaction editors. It does load TipTap's extensions: rich text comparison keys parse with
+ * their schema.
  *
  * Registering a new interaction means adding its descriptor here and its editor in index.js
  */
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/Editor.vue b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/Editor.vue
index 30017aa6e8..d663179866 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/Editor.vue
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/Editor.vue
@@ -309,8 +309,9 @@
   import ClickableRegion from '../../components/ClickableRegion/index.vue';
   import EditableChipList from '../../components/EditableChipList/index.vue';
   import ShuffledResponsePool from '../../components/ShuffledResponsePool/index.vue';
-  import { hasRichTextContent, richTextComparisonKey } from '../../utils/richText';
+  import { hasRichTextContent } from '../../utils/richText';
   import TipTapEditor from 'shared/views/TipTapEditor/TipTapEditor/TipTapEditor';
+  import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
   import EditorImageProcessor from 'shared/views/TipTapEditor/TipTapEditor/services/imageService';
 
   /** Which card or chip list currently holds the open TipTap editor. */
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/__tests__/parse.spec.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/__tests__/parse.spec.js
index 9f0e6f1469..7bf8dd43a0 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/__tests__/parse.spec.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/__tests__/parse.spec.js
@@ -23,6 +23,9 @@ const declaration = (...values) =>
     <qti-correct-response>${values.map(v => `<qti-value>${v}</qti-value>`).join('')}</qti-correct-response>
   </qti-response-declaration>`;
 
+const SOLVE_X2 = '<p>Solve <span data-latex="x^2"></span> for x</p>';
+const SOLVE_Y3 = '<p>Solve <span data-latex="y^3"></span> for x</p>';
+
 const ROWS = matchSet(choice('row_dog', 'Dog') + choice('row_eagle', 'Eagle'));
 const RESPONSES = matchSet(
   choice('choice_mammal', 'Mammal') + choice('choice_bird', 'Bird') + choice('choice_fur', 'Fur'),
@@ -484,6 +487,27 @@ describe('parse → buildXML → parse round-trip', () => {
     expect(roundTrip(state)).toEqual(state);
   });
 
+  it.each([
+    ['formulas', SOLVE_X2, SOLVE_Y3],
+    [
+      'SVGs',
+      '<p><svg><circle r="1"></circle></svg></p>',
+      '<p><svg><rect width="2"></rect></svg></p>',
+    ],
+    ['scripts', '<p>x<sup>2</sup></p>', '<p>x<sub>2</sub></p>'],
+  ])('preserves answers that differ only in their %s', (_, first, second) => {
+    const state = {
+      responseIdentifier: 'RESPONSE',
+      prompt: '',
+      rows: [
+        { id: 'row_dog', content: 'Dog', matches: [{ id: 'choice_a', content: first }] },
+        { id: 'row_eagle', content: 'Eagle', matches: [{ id: 'choice_b', content: second }] },
+      ],
+      distractors: [],
+    };
+    expect(matchContents(roundTrip(state).rows)).toEqual([[first], [second]]);
+  });
+
   it('preserves the default state', () => {
     const original = parse('', []);
     expect(roundTrip(original)).toEqual(original);
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/__tests__/validation.spec.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/__tests__/validation.spec.js
index 79e6d1546d..e6f74c2a84 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/__tests__/validation.spec.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/__tests__/validation.spec.js
@@ -1,6 +1,6 @@
 import { validateMatchInteraction as validate } from '../validation';
 import { ValidationError } from '../../../constants';
-import { richTextComparisonKey } from '../../../utils/richText';
+import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
 
 const row = (index, content, matches) => ({ id: `row_${index}`, content, matches });
 const answer = (id, content) => ({ id, content });
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/parse.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/parse.js
index ae39c65d61..c498bc8e4a 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/parse.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/parse.js
@@ -2,9 +2,10 @@ import { QTIDeclaration } from '../../serialization/qti/QTIDeclaration';
 import { buildXmlNode, getContentHTML, getPromptHTML, parseXML } from '../../serialization/xml';
 import CorrectResponse from '../../serialization/qti/declarations/correctResponse';
 import { generateRandomSlug } from '../../utils/generateRandomSlug';
-import { hasRichTextContent, richTextComparisonKey } from '../../utils/richText';
+import { hasRichTextContent } from '../../utils/richText';
 import { RESPONSE_IDENTIFIER } from '../../constants';
 import { _extractCorrectPairIds, newChoice } from '../associate/parse';
+import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
 
 const serializer = new XMLSerializer();
 
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/validation.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/validation.js
index a2e93bf78a..71195193e1 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/validation.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/match/validation.js
@@ -1,5 +1,6 @@
 import { ValidationError } from '../../constants';
-import { hasRichTextContent, richTextComparisonKey } from '../../utils/richText';
+import { hasRichTextContent } from '../../utils/richText';
+import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
 
 /**
  * Validate MatchState → ValidationError[].
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/ordering/__tests__/validation.spec.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/ordering/__tests__/validation.spec.js
index f8856eaf52..ee9aa92444 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/ordering/__tests__/validation.spec.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/ordering/__tests__/validation.spec.js
@@ -157,5 +157,19 @@ describe('validateOrderingInteraction()', () => {
         ValidationError.DUPLICATE_CHOICE_CONTENT,
       );
     });
+
+    it.each([
+      ['a formula', '<span data-latex="x^2"></span>', '<span data-latex="y^3"></span>'],
+      ['an image', '<img src="abc123.png"/>', '<img src="def456.png"/>'],
+      ['a script', '<sup>2</sup>', '<sub>2</sub>'],
+    ])('does not flag items with the same text but %s that differs', (_, first, second) => {
+      const state = makeState({
+        items: [
+          makeItem({ id: 'a', content: `<p>Solve ${first} for x</p>` }),
+          makeItem({ id: 'b', content: `<p>Solve ${second} for x</p>` }),
+        ],
+      });
+      expect(validateOrderingInteraction(state)).toEqual([]);
+    });
   });
 });
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/ordering/validation.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/ordering/validation.js
index bc8e68d0c1..4f60436825 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/ordering/validation.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/interactions/ordering/validation.js
@@ -1,5 +1,6 @@
 import { ValidationError } from '../../constants';
-import { hasRichTextContent, richTextComparisonKey } from '../../utils/richText';
+import { hasRichTextContent } from '../../utils/richText';
+import { richTextComparisonKey } from 'shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey';
 
 /**
  * Validate OrderingState → ValidationError[].
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/utils/__tests__/richText.spec.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/utils/__tests__/richText.spec.js
index d398d94b0c..982a2d359f 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/utils/__tests__/richText.spec.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/utils/__tests__/richText.spec.js
@@ -1,4 +1,4 @@
-import { hasRichTextContent, richTextComparisonKey } from '../richText';
+import { hasRichTextContent } from '../richText';
 
 describe('hasRichTextContent', () => {
   it.each([
@@ -32,29 +32,3 @@ describe('hasRichTextContent', () => {
     expect(hasRichTextContent(content)).toBe(expected);
   });
 });
-
-describe('richTextComparisonKey', () => {
-  it('reads through markup, so the same words marked up differently are one key', () => {
-    expect(richTextComparisonKey('<p><strong>Paris</strong></p>')).toBe(
-      richTextComparisonKey('<p>Paris</p>'),
-    );
-  });
-
-  it('keeps two different formulas apart when there is no text to compare', () => {
-    expect(richTextComparisonKey('<p><span data-latex="x^2"></span></p>')).not.toBe(
-      richTextComparisonKey('<p><span data-latex="y^2"></span></p>'),
-    );
-  });
-
-  it('keeps two different images apart when there is no text to compare', () => {
-    expect(richTextComparisonKey('<p><img src="a.png"/></p>')).not.toBe(
-      richTextComparisonKey('<p><img src="b.png"/></p>'),
-    );
-  });
-
-  it('still matches the same image offered twice', () => {
-    expect(richTextComparisonKey('<p><img src="a.png"/></p>')).toBe(
-      richTextComparisonKey('<p>\n  <img src="a.png"/>\n</p>'),
-    );
-  });
-});
diff --git a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/utils/richText.js b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/utils/richText.js
index 622a3f823b..9ead9a85fe 100644
--- a/contentcuration/contentcuration/frontend/shared/views/QTIEditor/utils/richText.js
+++ b/contentcuration/contentcuration/frontend/shared/views/QTIEditor/utils/richText.js
@@ -49,21 +49,3 @@ export function hasRichTextContent(content) {
     Boolean(parseXML(content ?? '', 'text/html').querySelector(EMBEDDED_MEDIA))
   );
 }
-
-/**
- * A key two fragments can be compared on to tell whether they say the same thing.
- *
- * Text is what an author reads, so text is what duplicates are judged on — two choices
- * that read the same are the same choice however differently they are marked up. A
- * fragment with no text has only its markup to go on, which keeps two different images
- * apart while still catching the same image offered twice — read back out of stored XML
- * it arrives pretty-printed, so the markup is compared with its layout normalised away.
- *
- * Only meaningful for a fragment that `hasRichTextContent`; an empty one keys to ''.
- *
- * @param {string} content - HTML fragment from a TipTap editor
- * @returns {string}
- */
-export function richTextComparisonKey(content) {
-  return toText(content) || (content ?? '').replace(/\s+/g, ' ').replace(/>\s+</g, '><').trim();
-}
diff --git a/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/TipTapEditor/composables/useEditor.js b/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/TipTapEditor/composables/useEditor.js
index b57916c10f..e416af5955 100644
--- a/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/TipTapEditor/composables/useEditor.js
+++ b/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/TipTapEditor/composables/useEditor.js
@@ -30,6 +30,39 @@ const INLINE_ONLY_STARTER_KIT = {
   trailingNode: false,
 };
 
+export function editorExtensions({ inlineOnly = false } = {}) {
+  return [
+    StarterKitExtension.configure({
+      codeBlock: false, // Disable default code block to use the extended version
+      // A link has nothing to navigate to on a device with no internet access, so
+      // the editor offers none and the legacy conversion unwraps the ones it finds
+      // (utils/assessment/qti/convert.py). Dropping the mark rather than only the
+      // toolbar button is what keeps a pasted anchor from arriving as one.
+      link: false,
+      // Replaced by the versions in extensions/TextDecoration.js, which write the
+      // decoration as a style on a <span> — the QTI 3.0 HTML profile has no <u> or <s>.
+      strike: false,
+      underline: false,
+      ...(inlineOnly && INLINE_ONLY_STARTER_KIT),
+    }),
+    ...(inlineOnly
+      ? [InlineDocument]
+      : [
+          CodeBlockSyntaxHighlight,
+          Small,
+          Image,
+          TextAlign.configure({
+            types: ['heading', 'paragraph', 'image', 'small'],
+          }),
+        ]),
+    StyledStrike,
+    StyledUnderline,
+    Superscript,
+    Subscript,
+    Math,
+  ];
+}
+
 // Whether replacing the selection would delete a line break, welding two lines.
 function spansLines({ doc, selection }) {
   if (selection.empty) return false;
@@ -64,37 +97,7 @@ export function useEditor() {
     editor.value = new Editor({
       autofocus,
       editable: mode === 'edit',
-      extensions: [
-        StarterKitExtension.configure({
-          codeBlock: false, // Disable default code block to use the extended version
-          // A link has nothing to navigate to on a device with no internet access, so
-          // the editor offers none and the legacy conversion unwraps the ones it finds
-          // (utils/assessment/qti/convert.py). Dropping the mark rather than only the
-          // toolbar button is what keeps a pasted anchor from arriving as one.
-          link: false,
-          // Replaced by the versions in extensions/TextDecoration.js, which write the
-          // decoration as a style on a <span> — the QTI 3.0 HTML profile has no <u> or <s>.
-          strike: false,
-          underline: false,
-          ...(inlineOnly && INLINE_ONLY_STARTER_KIT),
-        }),
-        ...(inlineOnly
-          ? [InlineDocument]
-          : [
-              CodeBlockSyntaxHighlight,
-              Small,
-              Image,
-              TextAlign.configure({
-                types: ['heading', 'paragraph', 'image', 'small'],
-              }),
-            ]),
-        StyledStrike,
-        StyledUnderline,
-        Superscript,
-        Subscript,
-        Math,
-        ...extensions,
-      ],
+      extensions: [...editorExtensions({ inlineOnly }), ...extensions],
       content: content || '<p></p>',
       editorProps: {
         attributes: {
diff --git a/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey.js b/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey.js
new file mode 100644
index 0000000000..c3efd606f1
--- /dev/null
+++ b/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/TipTapEditor/utils/comparisonKey.js
@@ -0,0 +1,80 @@
+import omit from 'lodash/omit';
+import { getSchema } from '@tiptap/core';
+// The resolver does not read package `exports` subpaths.
+// eslint-disable-next-line import/no-unresolved
+import { DOMParser as PMDOMParser } from '@tiptap/pm/model';
+import { editorExtensions } from '../composables/useEditor';
+
+// The full schema, so inline and block content of the same text read the same.
+const schema = getSchema(editorExtensions());
+const parser = PMDOMParser.fromSchema(schema);
+
+// Media the schema has no node for, so parsing would drop it.
+const UNPARSED_MEDIA = 'svg, math';
+// Marks that change what text says.
+const SCRIPTS = ['superscript', 'subscript'];
+
+/**
+ * A key two fragments can be compared on to tell whether they say the same thing.
+ *
+ * Read as TipTap saves it, so its re-render of a fragment keys the same: its text,
+ * however marked up except its sub/superscripts, and each formula, image, SVG and
+ * MathML where it stands.
+ *
+ * @param {string} html - HTML fragment from a TipTap editor
+ * @returns {string}
+ */
+export function richTextComparisonKey(html) {
+  const document = new DOMParser().parseFromString(html ?? '', 'text/html');
+  // A formula stands in for each, so parsing keeps its place. HTML parsing turns NUL
+  // into U+FFFD, so no stored formula has this LaTeX.
+  const unparsed = new Map();
+  for (const element of document.body.querySelectorAll(UNPARSED_MEDIA)) {
+    const latex = `\0${unparsed.size}`;
+    unparsed.set(latex, ['html', element.outerHTML.replace(/\s+/g, ' ').replace(/>\s+</g, '><')]);
+    const placeholder = document.createElement('span');
+    placeholder.setAttribute('data-latex', latex);
+    element.replaceWith(placeholder);
+  }
+  const parts = [];
+  let text = '';
+  let script = null;
+  // Whitespace at a line's edges is not seen, nor kept by parsing TipTap's output, e.g.
+  // after an image split out of a paragraph.
+  let lineStart = false;
+  const endText = () => {
+    if (text) parts.push(script ? [script, text] : text);
+    text = '';
+  };
+  const read = node => {
+    if (node.isText) {
+      const nodeScript =
+        node.marks.find(mark => SCRIPTS.includes(mark.type.name))?.type.name ?? null;
+      if (nodeScript !== script) {
+        endText();
+        script = nodeScript;
+      }
+      const value = lineStart ? node.text.trimStart() : node.text;
+      lineStart = lineStart && !value;
+      text += value;
+    } else if (node.type.name === 'math') {
+      endText();
+      parts.push(unparsed.get(node.attrs.latex) ?? ['latex', node.attrs.latex]);
+      lineStart = false;
+    } else if (node.type.name === 'image') {
+      endText();
+      // Not where an upload is saved, nor the size ImageNodeView writes when it loads.
+      parts.push(['img', omit(node.attrs, ['permanentSrc', 'width', 'height'])]);
+      lineStart = false;
+    } else if (node.isTextblock || node.type.name === 'hardBreak') {
+      lineStart = true;
+      node.forEach(read);
+      text = text.trimEnd();
+    } else {
+      node.forEach(read);
+    }
+  };
+  read(parser.parse(document.body));
+  endText();
+  return JSON.stringify(parts);
+}
diff --git a/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/__tests__/comparisonKey.spec.js b/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/__tests__/comparisonKey.spec.js
new file mode 100644
index 0000000000..ac32857c7c
--- /dev/null
+++ b/contentcuration/contentcuration/frontend/shared/views/TipTapEditor/__tests__/comparisonKey.spec.js
@@ -0,0 +1,231 @@
+import { useEditor } from '../TipTapEditor/composables/useEditor';
+import { richTextComparisonKey } from '../TipTapEditor/utils/comparisonKey';
+
+describe('richTextComparisonKey', () => {
+  it('reads through markup, so the same words marked up differently are one key', () => {
+    expect(richTextComparisonKey('<p><strong>Par</strong>is</p>')).toBe(
+      richTextComparisonKey('<p>Paris</p>'),
+    );
+  });
+
+  it.each([
+    ['bold', '<p>x<strong>2</strong></p>'],
+    ['italic', '<p>x<em>2</em></p>'],
+    ['underline', '<p>x<span style="text-decoration: underline">2</span></p>'],
+    ['strikethrough', '<p>x<span style="text-decoration: line-through">2</span></p>'],
+  ])('reads %s as the same text', (_, marked) => {
+    expect(richTextComparisonKey(marked)).toBe(richTextComparisonKey('<p>x2</p>'));
+  });
+
+  it('keeps superscript, subscript and plain text apart', () => {
+    const keys = ['<p>x<sup>2</sup></p>', '<p>x<sub>2</sub></p>', '<p>x2</p>'].map(
+      richTextComparisonKey,
+    );
+    expect(new Set(keys).size).toBe(3);
+  });
+
+  it.each([
+    ['formula', '<span data-latex="x^2"></span>', '<span data-latex="y^2"></span>'],
+    ['image', '<img src="a.png"/>', '<img src="b.png"/>'],
+    ['SVG', '<svg><circle r="1"/></svg>', '<svg><rect width="2"/></svg>'],
+    ['MathML', '<math><mi>x</mi></math>', '<math><mi>y</mi></math>'],
+  ])('keeps two different %s apart', (_, first, second) => {
+    expect(richTextComparisonKey(`<p>${first}</p>`)).not.toBe(
+      richTextComparisonKey(`<p>${second}</p>`),
+    );
+    expect(richTextComparisonKey(`<p>a ${first}</p>`)).not.toBe(
+      richTextComparisonKey(`<p>a ${second}</p>`),
+    );
+  });
+
+  it('reads the same SVG laid out differently as one', () => {
+    expect(richTextComparisonKey('<p><svg><circle r="1"/></svg></p>')).toBe(
+      richTextComparisonKey('<p>\n  <svg>\n    <circle r="1"/>\n  </svg>\n</p>'),
+    );
+  });
+
+  it.each([
+    ['formula', '<span data-latex="x^2"></span>'],
+    ['MathML', '<math><mn>5</mn></math>'],
+    ['SVG', '<svg><circle r="1"/></svg>'],
+  ])('keeps the same text and %s apart when it moves', (_, media) => {
+    expect(richTextComparisonKey(`<p>${media} cm</p>`)).not.toBe(
+      richTextComparisonKey(`<p>cm ${media}</p>`),
+    );
+    expect(richTextComparisonKey(`<p>a${media}b</p>`)).not.toBe(
+      richTextComparisonKey(`<p>ab${media}</p>`),
+    );
+  });
+
+  it('keeps a formula apart from its LaTeX typed as text', () => {
+    expect(richTextComparisonKey('<p>a <span data-latex="x^2"></span></p>')).not.toBe(
+      richTextComparisonKey('<p>a x^2</p>'),
+    );
+  });
+
+  it('keeps a formula apart from its key typed as text', () => {
+    const key = richTextComparisonKey('<p>a <span data-latex="x^2"></span></p>');
+    expect(richTextComparisonKey(`<p>${key}</p>`)).not.toBe(key);
+  });
+
+  describe.each([
+    ['beside text', 'see '],
+    ['alone', ''],
+  ])('an image %s', (_, text) => {
+    const key = image => richTextComparisonKey(`<p>${text}${image}</p>`);
+
+    it.each([
+      ['alt text', '<img src="a.png" alt="a cat"/>', '<img src="a.png" alt="a dog"/>'],
+      ['alignment', '<img src="a.png"/>', '<img src="a.png" data-text-align="center"/>'],
+      ['style', '<img src="a.png"/>', '<img src="a.png" style="text-align: center"/>'],
+    ])('is kept apart when its %s differs', (_, first, second) => {
+      expect(key(first)).not.toBe(key(second));
+    });
+
+    it('reads attribute order and the default alignment as the same image', () => {
+      expect(key('<img alt="a cat" src="a.png">')).toBe(
+        key('<img src="a.png" style="text-align: left" alt="a cat">'),
+      );
+    });
+
+    it('reads the same image at another size as the same image', () => {
+      expect(key('<img src="a.png" width="100" height="50"/>')).toBe(key('<img src="a.png"/>'));
+    });
+
+    it.each([
+      ['title', '<img src="a.png" title="t"/>'],
+      ['class', '<img src="a.png" class="wide"/>'],
+      ['size style', '<img src="a.png" style="width: 50%"/>'],
+      ['saved upload', '<img src="a.png" permanentsrc="https://storage/a.png"/>'],
+    ])('with a %s it does not show reads as the same image', (_, other) => {
+      expect(key(other)).toBe(key('<img src="a.png"/>'));
+    });
+  });
+
+  it.each([
+    ['formula', '<span data-latex="a"></span>', '<span data-latex="b"></span>'],
+    ['image', '<img src="a.png"/>', '<img src="b.png"/>'],
+    ['MathML', '<math><mi>a</mi></math>', '<math><mi>b</mi></math>'],
+  ])('keeps the same code apart when its %s differs', (_, first, second) => {
+    expect(richTextComparisonKey(`<pre><code>x ${first}</code></pre>`)).not.toBe(
+      richTextComparisonKey(`<pre><code>x ${second}</code></pre>`),
+    );
+  });
+
+  it('keeps the indentation of a code block', () => {
+    expect(richTextComparisonKey('<pre><code>if x:\n    return 1</code></pre>')).not.toBe(
+      richTextComparisonKey('<pre><code>if x:\n  return 1</code></pre>'),
+    );
+  });
+
+  it.each([
+    ['paragraphs', '<p>a</p><p>b</p>'],
+    ['a line break', '<p>a<br>b</p>'],
+    ['list items', '<ul><li>a</li><li>b</li></ul>'],
+  ])('reads text split over %s as the same text on one line', (_, split) => {
+    expect(richTextComparisonKey(split)).toBe(richTextComparisonKey('<p>ab</p>'));
+  });
+
+  it('reads text in a code block as the same text in a paragraph', () => {
+    expect(richTextComparisonKey('<pre><code>ab</code></pre>')).toBe(
+      richTextComparisonKey('<p>ab</p>'),
+    );
+  });
+
+  it.each([
+    ['a trailing', '<p>Paris&nbsp;</p>'],
+    ['a leading', '<p>&nbsp;Paris</p>'],
+    ['an empty paragraph of', '<p>Paris</p><p>&nbsp;</p>'],
+    ['a line-break-ended', '<p>Paris&nbsp;<br>&nbsp;</p>'],
+  ])('drops %s non-breaking space', (_, padded) => {
+    expect(richTextComparisonKey(padded)).toBe(richTextComparisonKey('<p>Paris</p>'));
+  });
+
+  it.each([
+    ['<p>Paris&nbsp;</p><p><img src="a.png"/></p>', '<p>Paris</p><p><img src="a.png"/></p>'],
+    [
+      '<p><span data-latex="x"></span>&nbsp;</p><p>a</p>',
+      '<p><span data-latex="x"></span></p><p>a</p>',
+    ],
+  ])('drops a non-breaking space at the end of a line in %j', (padded, plain) => {
+    expect(richTextComparisonKey(padded)).toBe(richTextComparisonKey(plain));
+  });
+
+  it('keeps a non-breaking space inside text apart from a space', () => {
+    expect(richTextComparisonKey('<p>a&nbsp;b</p>')).not.toBe(richTextComparisonKey('<p>a b</p>'));
+  });
+
+  it('reads an entity in plain text as the character it stands for', () => {
+    expect(richTextComparisonKey('Salt &amp; pepper')).toBe(
+      richTextComparisonKey('<p>Salt &amp; pepper</p>'),
+    );
+  });
+
+  describe('after TipTap rewraps it', () => {
+    let editors = [];
+
+    const rewrap = (html, edit = () => {}) => {
+      const { initializeEditor, editor } = useEditor();
+      initializeEditor(html);
+      editors.push(editor.value);
+      edit(editor.value);
+      return editor.value.getHTML();
+    };
+
+    afterEach(() => {
+      editors.forEach(editor => editor.destroy());
+      editors = [];
+    });
+
+    it.each([
+      '<p>see <img src="a.png"/> here</p>',
+      '<p>\n  <img src="a.png"/>\n  caption\n</p>',
+      '<p>see <img alt="a cat" src="H.png" /></p>',
+      '<p>Solve\n  <span data-latex="x^2"></span>\n  for x</p>',
+      '<p>a</p>\n<p><span data-latex="x"></span></p>',
+      '<p>a</p>\n<p>\n  <span data-latex="x"></span>\n</p>',
+      '<p>see <img src="a.png" title="t"/></p>',
+      '<img src="a.png"/>',
+      '<p><img alt="a cat" src="a.png"/></p>',
+      '<p><img src="a.png" title="t"/></p>',
+      '<pre><code>if x:\n    return 1</code></pre>',
+      '<p>a<br>b</p>',
+      '<p>a <br>\n  b</p>',
+    ])('%j keys the same', stored => {
+      expect(richTextComparisonKey(rewrap(stored))).toBe(richTextComparisonKey(stored));
+    });
+
+    it('keys an image sized when it loads the same as unsized', () => {
+      const stored = '<p>see <img src="a.png"/></p>';
+      // As ImageNodeView does once the image loads.
+      const resizeImages = editor =>
+        editor.state.doc.descendants((node, pos) => {
+          if (node.type.name === 'image') {
+            editor.view.dispatch(
+              editor.state.tr.setNodeMarkup(pos, null, { ...node.attrs, width: 300, height: 200 }),
+            );
+          }
+        });
+      expect(richTextComparisonKey(rewrap(stored, resizeImages))).toBe(
+        richTextComparisonKey(stored),
+      );
+    });
+  });
+
+  it('keeps the spaces around a formula', () => {
+    expect(richTextComparisonKey('<p>a <span data-latex="x"></span> b</p>')).not.toBe(
+      richTextComparisonKey('<p>a<span data-latex="x"></span>b</p>'),
+    );
+  });
+
+  it.each([
+    ['in text', '<p>a  b</p>', '<p>a b</p>'],
+    [
+      'beside a formula',
+      '<p>a  <span data-latex="x"></span></p>',
+      '<p>a <span data-latex="x"></span></p>',
+    ],
+  ])('collapses runs of whitespace %s', (_, run, single) => {
+    expect(richTextComparisonKey(run)).toBe(richTextComparisonKey(single));
+  });
+});