diff --git a/src/content-tags-drawer/ContentTagsDrawer.test.jsx b/src/content-tags-drawer/ContentTagsDrawer.test.jsx
index 8abd78e1fb..75ffe35b79 100644
--- a/src/content-tags-drawer/ContentTagsDrawer.test.jsx
+++ b/src/content-tags-drawer/ContentTagsDrawer.test.jsx
@@ -55,10 +55,6 @@ describe('<ContentTagsDrawer />', () => {
     initializeMocks();
   });
 
-  afterEach(() => {
-    jest.clearAllMocks();
-  });
-
   it('should render page and page title correctly', () => {
     renderDrawer(stagedTagsId);
     expect(screen.getByText('Manage tags')).toBeInTheDocument();
diff --git a/src/editors/Editor.test.jsx b/src/editors/Editor.test.jsx
deleted file mode 100644
index fa19e60689..0000000000
--- a/src/editors/Editor.test.jsx
+++ /dev/null
@@ -1,55 +0,0 @@
-import 'CourseAuthoring/editors/setupEditorTest';
-import React from 'react';
-import { useDispatch } from 'react-redux';
-import { shallow } from '@edx/react-unit-test-utils';
-import Editor from './Editor';
-import supportedEditors from './supportedEditors';
-import * as hooks from './hooks';
-import { blockTypes } from './data/constants/app';
-
-jest.mock('./hooks', () => ({
-  initializeApp: jest.fn(),
-}));
-
-jest.mock('./containers/TextEditor', () => 'TextEditor');
-jest.mock('./containers/VideoEditor', () => 'VideoEditor');
-jest.mock('./containers/ProblemEditor', () => 'ProblemEditor');
-
-const initData = {
-  blockId: 'block-v1:edX+DemoX+Demo_Course+type@html+block@030e35c4756a4ddc8d40b95fbbfff4d4',
-  blockType: blockTypes.html,
-  learningContextId: 'course-v1:edX+DemoX+Demo_Course',
-  lmsEndpointUrl: 'evenfakerurl.com',
-  studioEndpointUrl: 'fakeurl.com',
-};
-const props = {
-  initialize: jest.fn(),
-  onClose: jest.fn().mockName('props.onClose'),
-  courseId: 'course-v1:edX+DemoX+Demo_Course',
-  ...initData,
-};
-
-let el;
-describe('Editor', () => {
-  describe('render', () => {
-    test('snapshot: renders correct editor given blockType (html -> TextEditor)', () => {
-      expect(shallow(<Editor {...props} />).snapshot).toMatchSnapshot();
-    });
-    test('presents error message if no relevant editor found and ref ready', () => {
-      expect(shallow(<Editor {...props} blockType="fAkEBlock" />).snapshot).toMatchSnapshot();
-    });
-    test.each(Object.values(blockTypes))('renders %p editor when ref is ready', (blockType) => {
-      el = shallow(<Editor {...props} blockType={blockType} />);
-      expect(el.shallowWrapper.props.children.props.children.type).toBe(supportedEditors[blockType]);
-    });
-  });
-  describe('behavior', () => {
-    it('calls initializeApp hook with dispatch, and passed data', () => {
-      el = shallow(<Editor {...props} blockType={blockTypes.html} />);
-      expect(hooks.initializeApp).toHaveBeenCalledWith({
-        dispatch: useDispatch(),
-        data: initData,
-      });
-    });
-  });
-});
diff --git a/src/editors/Editor.tsx b/src/editors/Editor.tsx
index cc42647f56..8e52448242 100644
--- a/src/editors/Editor.tsx
+++ b/src/editors/Editor.tsx
@@ -1,3 +1,5 @@
+// Note: there is no Editor.test.tsx. This component only works together with
+// <EditorPage> as its parent, so they are tested together in EditorPage.test.tsx
 import React from 'react';
 import { useDispatch } from 'react-redux';
 import { FormattedMessage } from '@edx/frontend-platform/i18n';
@@ -7,6 +9,7 @@ import * as hooks from './hooks';
 
 import supportedEditors from './supportedEditors';
 import type { EditorComponent } from './EditorComponent';
+import { useEditorContext } from './EditorContext';
 
 export interface Props extends EditorComponent {
   blockType: string;
@@ -14,6 +17,7 @@ export interface Props extends EditorComponent {
   learningContextId: string | null;
   lmsEndpointUrl: string | null;
   studioEndpointUrl: string | null;
+  fullScreen?: boolean;
 }
 
 const Editor: React.FC<Props> = ({
@@ -36,23 +40,29 @@ const Editor: React.FC<Props> = ({
       studioEndpointUrl,
     },
   });
+  const { fullScreen } = useEditorContext();
 
   const EditorComponent = supportedEditors[blockType];
-  return (
-    <div
-      className="d-flex flex-column"
-    >
+  const innerEditor = (EditorComponent !== undefined)
+    ? <EditorComponent {...{ onClose, returnFunction }} />
+    : <FormattedMessage {...messages.couldNotFindEditor} />;
+
+  if (fullScreen) {
+    return (
       <div
-        className="pgn__modal-fullscreen h-100"
-        role="dialog"
-        aria-label={blockType}
+        className="d-flex flex-column"
       >
-        {(EditorComponent !== undefined)
-          ? <EditorComponent {...{ onClose, returnFunction }} />
-          : <FormattedMessage {...messages.couldNotFindEditor} />}
+        <div
+          className="pgn__modal-fullscreen h-100"
+          role="dialog"
+          aria-label={blockType}
+        >
+          {innerEditor}
+        </div>
       </div>
-    </div>
-  );
+    );
+  }
+  return innerEditor;
 };
 
 export default Editor;
diff --git a/src/editors/EditorContext.tsx b/src/editors/EditorContext.tsx
new file mode 100644
index 0000000000..e43b60a815
--- /dev/null
+++ b/src/editors/EditorContext.tsx
@@ -0,0 +1,39 @@
+import React from 'react';
+
+/**
+ * Shared context that's used by all our editors.
+ *
+ * Note: we're in the process of moving things from redux into this.
+ */
+export interface EditorContext {
+  learningContextId: string;
+  /**
+   * When editing components in the libraries part of the Authoring MFE, we show
+   * the editors in a modal (fullScreen = false). This is the preferred approach
+   * so that authors can see context behind the modal.
+   * However, when making edits from the legacy course view, we display the
+   * editors in a fullscreen view. This approach is deprecated.
+   */
+  fullScreen: boolean;
+}
+
+const context = React.createContext<EditorContext | undefined>(undefined);
+
+/** Hook to get the editor context (shared context) */
+export function useEditorContext() {
+  const ctx = React.useContext(context);
+  if (ctx === undefined) {
+    /* istanbul ignore next */
+    throw new Error('This component needs to be wrapped in <EditorContextProvider>');
+  }
+  return ctx;
+}
+
+export const EditorContextProvider: React.FC<{
+  children: React.ReactNode,
+  learningContextId: string;
+  fullScreen: boolean;
+}> = ({ children, ...contextData }) => {
+  const ctx: EditorContext = React.useMemo(() => ({ ...contextData }), []);
+  return <context.Provider value={ctx}>{children}</context.Provider>;
+};
diff --git a/src/editors/EditorPage.jsx b/src/editors/EditorPage.jsx
deleted file mode 100644
index 60de6e1cc6..0000000000
--- a/src/editors/EditorPage.jsx
+++ /dev/null
@@ -1,58 +0,0 @@
-import React from 'react';
-import PropTypes from 'prop-types';
-import { Provider } from 'react-redux';
-
-import store from './data/store';
-import Editor from './Editor';
-import ErrorBoundary from './sharedComponents/ErrorBoundary';
-
-const EditorPage = ({
-  courseId,
-  blockType,
-  blockId,
-  lmsEndpointUrl,
-  studioEndpointUrl,
-  onClose,
-  returnFunction,
-}) => (
-  <Provider store={store}>
-    <ErrorBoundary
-      {...{
-        learningContextId: courseId,
-        studioEndpointUrl,
-      }}
-    >
-      <Editor
-        {...{
-          onClose,
-          learningContextId: courseId,
-          blockType,
-          blockId,
-          lmsEndpointUrl,
-          studioEndpointUrl,
-          returnFunction,
-        }}
-      />
-    </ErrorBoundary>
-  </Provider>
-);
-EditorPage.defaultProps = {
-  blockId: null,
-  courseId: null,
-  lmsEndpointUrl: null,
-  onClose: null,
-  returnFunction: null,
-  studioEndpointUrl: null,
-};
-
-EditorPage.propTypes = {
-  blockId: PropTypes.string,
-  blockType: PropTypes.string.isRequired,
-  courseId: PropTypes.string,
-  lmsEndpointUrl: PropTypes.string,
-  onClose: PropTypes.func,
-  returnFunction: PropTypes.func,
-  studioEndpointUrl: PropTypes.string,
-};
-
-export default EditorPage;
diff --git a/src/editors/EditorPage.test.jsx b/src/editors/EditorPage.test.jsx
deleted file mode 100644
index 24dfffe293..0000000000
--- a/src/editors/EditorPage.test.jsx
+++ /dev/null
@@ -1,32 +0,0 @@
-import React from 'react';
-import { shallow } from '@edx/react-unit-test-utils';
-import EditorPage from './EditorPage';
-
-const props = {
-  courseId: 'course-v1:edX+DemoX+Demo_Course',
-  blockType: 'html',
-  blockId: 'block-v1:edX+DemoX+Demo_Course+type@html+block@030e35c4756a4ddc8d40b95fbbfff4d4',
-  lmsEndpointUrl: 'evenfakerurl.com',
-  studioEndpointUrl: 'fakeurl.com',
-  onClose: jest.fn().mockName('props.onClose'),
-};
-jest.mock('react-redux', () => ({
-  Provider: 'Provider',
-  connect: (mapStateToProps, mapDispatchToProps) => (component) => ({
-    mapStateToProps,
-    mapDispatchToProps,
-    component,
-  }),
-}));
-jest.mock('./Editor', () => 'Editor');
-
-describe('Editor Page', () => {
-  describe('snapshots', () => {
-    test('rendering correctly with expected Input', () => {
-      expect(shallow(<EditorPage {...props} />).snapshot).toMatchSnapshot();
-    });
-    test('props besides blockType default to null', () => {
-      expect(shallow(<EditorPage blockType={props.blockType} />).snapshot).toMatchSnapshot();
-    });
-  });
-});
diff --git a/src/editors/EditorPage.test.tsx b/src/editors/EditorPage.test.tsx
new file mode 100644
index 0000000000..e4d0de4091
--- /dev/null
+++ b/src/editors/EditorPage.test.tsx
@@ -0,0 +1,98 @@
+import { snakeCaseObject } from '@edx/frontend-platform';
+import {
+  render,
+  screen,
+  initializeMocks,
+} from '../testUtils';
+import editorCmsApi from './data/services/cms/api';
+
+import EditorPage from './EditorPage';
+
+// Mock this plugins component:
+jest.mock('frontend-components-tinymce-advanced-plugins', () => ({ a11ycheckerCss: '' }));
+// Always mock out the "fetch course images" endpoint:
+jest.spyOn(editorCmsApi, 'fetchImages').mockImplementation(async () => ( // eslint-disable-next-line
+  { data: { assets: [], start: 0, end: 0, page: 0, pageSize: 50, totalCount: 0 } }
+));
+// Mock out the 'get ancestors' API:
+jest.spyOn(editorCmsApi, 'fetchByUnitId').mockImplementation(async () => ({
+  status: 200,
+  data: {
+    ancestors: [{
+      id: 'block-v1:Org+TS100+24+type@vertical+block@parent',
+      display_name: 'You-Knit? The Test Unit',
+      category: 'vertical',
+      has_children: true,
+    }],
+  },
+}));
+
+const defaultPropsHtml = {
+  blockId: 'block-v1:Org+TS100+24+type@html+block@123456html',
+  blockType: 'html',
+  courseId: 'course-v1:Org+TS100+24',
+  lmsEndpointUrl: 'http://lms.test.none/',
+  studioEndpointUrl: 'http://cms.test.none/',
+  onClose: jest.fn(),
+  fullScreen: false,
+};
+const fieldsHtml = {
+  displayName: 'Introduction to Testing',
+  data: '<p>This is a text component which uses <strong>HTML</strong>.</p>',
+  metadata: { displayName: 'Introduction to Testing' },
+};
+
+describe('EditorPage', () => {
+  beforeEach(() => {
+    initializeMocks();
+  });
+
+  test('it can display the Text (html) editor in a modal', async () => {
+    jest.spyOn(editorCmsApi, 'fetchBlockById').mockImplementationOnce(async () => (
+      { status: 200, data: snakeCaseObject(fieldsHtml) }
+    ));
+
+    render(<EditorPage {...defaultPropsHtml} />);
+
+    // Then the editor should open
+    expect(await screen.findByRole('heading', { name: /Introduction to Testing/ })).toBeInTheDocument();
+
+    const modalElement = screen.getByRole('dialog');
+    expect(modalElement.classList).toContain('pgn__modal');
+    expect(modalElement.classList).toContain('pgn__modal-xl');
+    expect(modalElement.classList).not.toContain('pgn__modal-fullscreen');
+  });
+
+  test('it can display the Text (html) editor as a full page (when coming from the legacy UI)', async () => {
+    jest.spyOn(editorCmsApi, 'fetchBlockById').mockImplementationOnce(async () => (
+      { status: 200, data: snakeCaseObject(fieldsHtml) }
+    ));
+
+    render(<EditorPage {...defaultPropsHtml} fullScreen />);
+
+    // Then the editor should open
+    expect(await screen.findByRole('heading', { name: /Introduction to Testing/ })).toBeInTheDocument();
+
+    const modalElement = screen.getByRole('dialog');
+    expect(modalElement.classList).toContain('pgn__modal-fullscreen');
+    expect(modalElement.classList).not.toContain('pgn__modal');
+    expect(modalElement.classList).not.toContain('pgn__modal-xl');
+  });
+
+  test('it shows an error message if there is no corresponding editor', async () => {
+    // We can edit 'html', 'problem', and 'video' blocks.
+    // But if we try to edit some other type, say 'fake', we should get an error:
+    jest.spyOn(editorCmsApi, 'fetchBlockById').mockImplementationOnce(async () => ( // eslint-disable-next-line
+      { status: 200, data: { display_name: 'Fake Un-editable Block', category: 'fake', metadata: {}, data: '' } }
+    ));
+
+    const defaultPropsFake = {
+      ...defaultPropsHtml,
+      blockId: 'block-v1:Org+TS100+24+type@fake+block@123456fake',
+      blockType: 'fake',
+    };
+    render(<EditorPage {...defaultPropsFake} />);
+
+    expect(await screen.findByText('Error: Could Not find Editor')).toBeInTheDocument();
+  });
+});
diff --git a/src/editors/EditorPage.tsx b/src/editors/EditorPage.tsx
new file mode 100644
index 0000000000..a0dd365954
--- /dev/null
+++ b/src/editors/EditorPage.tsx
@@ -0,0 +1,58 @@
+import React from 'react';
+import { Provider } from 'react-redux';
+
+import store from './data/store';
+import Editor from './Editor';
+import ErrorBoundary from './sharedComponents/ErrorBoundary';
+import { EditorComponent } from './EditorComponent';
+import { EditorContextProvider } from './EditorContext';
+
+interface Props extends EditorComponent {
+  blockId?: string;
+  blockType: string;
+  courseId: string;
+  lmsEndpointUrl?: string;
+  studioEndpointUrl?: string;
+  fullScreen?: boolean;
+  children?: never;
+}
+
+/**
+ * Wraps the editors with the redux state provider.
+ * TODO: refactor some of this to be React Context and React Query
+ */
+const EditorPage: React.FC<Props> = ({
+  courseId,
+  blockType,
+  blockId = null,
+  lmsEndpointUrl = null,
+  studioEndpointUrl = null,
+  onClose = null,
+  returnFunction = null,
+  fullScreen = true,
+}) => (
+  <Provider store={store}>
+    <ErrorBoundary
+      {...{
+        learningContextId: courseId,
+        studioEndpointUrl,
+      }}
+    >
+      <EditorContextProvider fullScreen={fullScreen} learningContextId={courseId}>
+        <Editor
+          {...{
+            onClose,
+            learningContextId: courseId,
+            blockType,
+            blockId,
+            lmsEndpointUrl,
+            studioEndpointUrl,
+            returnFunction,
+          }}
+        />
+      </EditorContextProvider>
+    </ErrorBoundary>
+  </Provider>
+);
+
+export default EditorPage;
diff --git a/src/editors/__snapshots__/Editor.test.jsx.snap b/src/editors/__snapshots__/Editor.test.jsx.snap
deleted file mode 100644
index 5c9cb23a39..0000000000
--- a/src/editors/__snapshots__/Editor.test.jsx.snap
+++ /dev/null
@@ -1,36 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`Editor render presents error message if no relevant editor found and ref ready 1`] = `
-<div
-  className="d-flex flex-column"
->
-  <div
-    aria-label="fAkEBlock"
-    className="pgn__modal-fullscreen h-100"
-    role="dialog"
-  >
-    <FormattedMessage
-      defaultMessage="Error: Could Not find Editor"
-      description="Error Message Dispayed When An unsopported Editor is desired in V2"
-      id="authoring.editorpage.selecteditor.error"
-    />
-  </div>
-</div>
-`;
-
-exports[`Editor render snapshot: renders correct editor given blockType (html -> TextEditor) 1`] = `
-<div
-  className="d-flex flex-column"
->
-  <div
-    aria-label="html"
-    className="pgn__modal-fullscreen h-100"
-    role="dialog"
-  >
-    <TextEditor
-      onClose={[MockFunction props.onClose]}
-      returnFunction={null}
-    />
-  </div>
-</div>
-`;
diff --git a/src/editors/__snapshots__/EditorPage.test.jsx.snap b/src/editors/__snapshots__/EditorPage.test.jsx.snap
deleted file mode 100644
index 7e15005764..0000000000
--- a/src/editors/__snapshots__/EditorPage.test.jsx.snap
+++ /dev/null
@@ -1,59 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`Editor Page snapshots props besides blockType default to null 1`] = `
-<Provider
-  store={
-    {
-      "dispatch": [Function],
-      "getState": [Function],
-      "replaceReducer": [Function],
-      "subscribe": [Function],
-      Symbol(Symbol.observable): [Function],
-    }
-  }
->
-  <ErrorBoundary
-    learningContextId={null}
-    studioEndpointUrl={null}
-  >
-    <Editor
-      blockId={null}
-      blockType="html"
-      learningContextId={null}
-      lmsEndpointUrl={null}
-      onClose={null}
-      returnFunction={null}
-      studioEndpointUrl={null}
-    />
-  </ErrorBoundary>
-</Provider>
-`;
-
-exports[`Editor Page snapshots rendering correctly with expected Input 1`] = `
-<Provider
-  store={
-    {
-      "dispatch": [Function],
-      "getState": [Function],
-      "replaceReducer": [Function],
-      "subscribe": [Function],
-      Symbol(Symbol.observable): [Function],
-    }
-  }
->
-  <ErrorBoundary
-    learningContextId="course-v1:edX+DemoX+Demo_Course"
-    studioEndpointUrl="fakeurl.com"
-  >
-    <Editor
-      blockId="block-v1:edX+DemoX+Demo_Course+type@html+block@030e35c4756a4ddc8d40b95fbbfff4d4"
-      blockType="html"
-      learningContextId="course-v1:edX+DemoX+Demo_Course"
-      lmsEndpointUrl="evenfakerurl.com"
-      onClose={[MockFunction props.onClose]}
-      returnFunction={null}
-      studioEndpointUrl="fakeurl.com"
-    />
-  </ErrorBoundary>
-</Provider>
-`;
diff --git a/src/editors/containers/EditorContainer/__snapshots__/index.test.jsx.snap b/src/editors/containers/EditorContainer/__snapshots__/index.test.jsx.snap
deleted file mode 100644
index 02c89e55d7..0000000000
--- a/src/editors/containers/EditorContainer/__snapshots__/index.test.jsx.snap
+++ /dev/null
@@ -1,161 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`EditorContainer component render snapshot: initialized. enable save and pass to header 1`] = `
-<div
-  className="editor-container d-flex flex-column position-relative zindex-0"
-  style={
-    {
-      "minHeight": "100%",
-    }
-  }
->
-  <BaseModal
-    bodyStyle={null}
-    close={[MockFunction closeCancelConfirmModal]}
-    confirmAction={
-      <Button
-        onClick={[Function]}
-        variant="primary"
-      >
-        <FormattedMessage
-          defaultMessage="OK"
-          description="Label for OK button"
-          id="authoring.editorContainer.okButton.label"
-        />
-      </Button>
-    }
-    footerAction={null}
-    headerComponent={null}
-    isFullscreenScroll={true}
-    isOpen={false}
-    size="md"
-    title="Exit the editor?"
-  >
-    <FormattedMessage
-      defaultMessage="Are you sure you want to exit the editor? Any unsaved changes will be lost."
-      description="Description text for modal confirming cancellation"
-      id="authoring.editorContainer.cancelConfirm.description"
-    />
-  </BaseModal>
-  <ModalDialog.Header
-    className="shadow-sm zindex-10"
-  >
-    <div
-      className="d-flex flex-row justify-content-between"
-    >
-      <h2
-        className="h3 col pl-0"
-      >
-        <injectIntl(ShimmedIntlComponent)
-          isInitialized={true}
-        />
-      </h2>
-      <IconButton
-        alt="Exit the editor"
-        iconAs="Icon"
-        onClick={[MockFunction openCancelConfirmModal]}
-        src={[MockFunction icons.Close]}
-      />
-    </div>
-  </ModalDialog.Header>
-  <ModalDialog.Body
-    className="pb-0 mb-6"
-  >
-    <h1>
-      My test content
-    </h1>
-  </ModalDialog.Body>
-  <injectIntl(ShimmedIntlComponent)
-    disableSave={false}
-    onCancel={[MockFunction openCancelConfirmModal]}
-    onSave={
-      {
-        "handleSaveClicked": {
-          "dispatch": [MockFunction react-redux.dispatch],
-          "getContent": [MockFunction props.getContent],
-          "returnFunction": [MockFunction props.returnFunction],
-          "validateEntry": [MockFunction props.validateEntry],
-        },
-      }
-    }
-  />
-</div>
-`;
-
-exports[`EditorContainer component render snapshot: not initialized. disable save and pass to header 1`] = `
-<div
-  className="editor-container d-flex flex-column position-relative zindex-0"
-  style={
-    {
-      "minHeight": "100%",
-    }
-  }
->
-  <BaseModal
-    bodyStyle={null}
-    close={[MockFunction closeCancelConfirmModal]}
-    confirmAction={
-      <Button
-        onClick={[Function]}
-        variant="primary"
-      >
-        <FormattedMessage
-          defaultMessage="OK"
-          description="Label for OK button"
-          id="authoring.editorContainer.okButton.label"
-        />
-      </Button>
-    }
-    footerAction={null}
-    headerComponent={null}
-    isFullscreenScroll={true}
-    isOpen={false}
-    size="md"
-    title="Exit the editor?"
-  >
-    <FormattedMessage
-      defaultMessage="Are you sure you want to exit the editor? Any unsaved changes will be lost."
-      description="Description text for modal confirming cancellation"
-      id="authoring.editorContainer.cancelConfirm.description"
-    />
-  </BaseModal>
-  <ModalDialog.Header
-    className="shadow-sm zindex-10"
-  >
-    <div
-      className="d-flex flex-row justify-content-between"
-    >
-      <h2
-        className="h3 col pl-0"
-      >
-        <injectIntl(ShimmedIntlComponent)
-          isInitialized={false}
-        />
-      </h2>
-      <IconButton
-        alt="Exit the editor"
-        iconAs="Icon"
-        onClick={[MockFunction openCancelConfirmModal]}
-        src={[MockFunction icons.Close]}
-      />
-    </div>
-  </ModalDialog.Header>
-  <ModalDialog.Body
-    className="pb-0 mb-6"
-  />
-  <injectIntl(ShimmedIntlComponent)
-    disableSave={true}
-    onCancel={[MockFunction openCancelConfirmModal]}
-    onSave={
-      {
-        "handleSaveClicked": {
-          "dispatch": [MockFunction react-redux.dispatch],
-          "getContent": [MockFunction props.getContent],
-          "returnFunction": [MockFunction props.returnFunction],
-          "validateEntry": [MockFunction props.validateEntry],
-        },
-      }
-    }
-  />
-</div>
-`;
diff --git a/src/editors/containers/EditorContainer/components/EditorFooter/__snapshots__/index.test.jsx.snap b/src/editors/containers/EditorContainer/components/EditorFooter/__snapshots__/index.test.jsx.snap
deleted file mode 100644
index dbfca713db..0000000000
--- a/src/editors/containers/EditorContainer/components/EditorFooter/__snapshots__/index.test.jsx.snap
+++ /dev/null
@@ -1,114 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`EditorFooter render snapshot: default args (disableSave: false, saveFailed: false) 1`] = `
-<div
-  className="editor-footer fixed-bottom"
->
-  <ModalDialog.Footer
-    className="shadow-sm"
-  >
-    <ActionRow>
-      <Button
-        aria-label="Discard changes and return to learning context"
-        onClick={[MockFunction args.onCancel]}
-        variant="tertiary"
-      >
-        <FormattedMessage
-          defaultMessage="Cancel"
-          description="Label for cancel button"
-          id="authoring.editorfooter.cancelButton.label"
-        />
-      </Button>
-      <Button
-        aria-label="Save changes and return to learning context"
-        disabled={false}
-        onClick={[MockFunction args.onSave]}
-      >
-        <FormattedMessage
-          defaultMessage="Save"
-          description="Label for Save button"
-          id="authoring.editorfooter.savebutton.label"
-        />
-      </Button>
-    </ActionRow>
-  </ModalDialog.Footer>
-</div>
-`;
-
-exports[`EditorFooter render snapshot: save disabled. Show button spinner 1`] = `
-<div
-  className="editor-footer fixed-bottom"
->
-  <ModalDialog.Footer
-    className="shadow-sm"
-  >
-    <ActionRow>
-      <Button
-        aria-label="Discard changes and return to learning context"
-        onClick={[MockFunction args.onCancel]}
-        variant="tertiary"
-      >
-        <FormattedMessage
-          defaultMessage="Cancel"
-          description="Label for cancel button"
-          id="authoring.editorfooter.cancelButton.label"
-        />
-      </Button>
-      <Button
-        aria-label="Save changes and return to learning context"
-        disabled={true}
-        onClick={[MockFunction args.onSave]}
-      >
-        <Spinner
-          animation="border"
-          className="mr-3"
-        />
-      </Button>
-    </ActionRow>
-  </ModalDialog.Footer>
-</div>
-`;
-
-exports[`EditorFooter render snapshot: save failed.  Show error message 1`] = `
-<div
-  className="editor-footer fixed-bottom"
->
-  <Toast
-    show={true}
-  >
-    <FormattedMessage
-      defaultMessage="Error: Content save failed. Please check recent changes and try again later."
-      description="Error message displayed when content fails to save."
-      id="authoring.editorfooter.save.error"
-    />
-  </Toast>
-  <ModalDialog.Footer
-    className="shadow-sm"
-  >
-    <ActionRow>
-      <Button
-        aria-label="Discard changes and return to learning context"
-        onClick={[MockFunction args.onCancel]}
-        variant="tertiary"
-      >
-        <FormattedMessage
-          defaultMessage="Cancel"
-          description="Label for cancel button"
-          id="authoring.editorfooter.cancelButton.label"
-        />
-      </Button>
-      <Button
-        aria-label="Save changes and return to learning context"
-        disabled={false}
-        onClick={[MockFunction args.onSave]}
-      >
-        <FormattedMessage
-          defaultMessage="Save"
-          description="Label for Save button"
-          id="authoring.editorfooter.savebutton.label"
-        />
-      </Button>
-    </ActionRow>
-  </ModalDialog.Footer>
-</div>
-`;
diff --git a/src/editors/containers/EditorContainer/components/EditorFooter/index.jsx b/src/editors/containers/EditorContainer/components/EditorFooter/index.jsx
deleted file mode 100644
index 20c2f2d560..0000000000
--- a/src/editors/containers/EditorContainer/components/EditorFooter/index.jsx
+++ /dev/null
@@ -1,64 +0,0 @@
-import React from 'react';
-import PropTypes from 'prop-types';
-
-import {
-  Spinner,
-  ActionRow,
-  Button,
-  ModalDialog,
-  Toast,
-} from '@openedx/paragon';
-import { FormattedMessage, injectIntl, intlShape } from '@edx/frontend-platform/i18n';
-
-import messages from './messages';
-
-const EditorFooter = ({
-  clearSaveFailed,
-  disableSave,
-  onCancel,
-  onSave,
-  saveFailed,
-  // injected
-  intl,
-}) => (
-  <div className="editor-footer fixed-bottom">
-    {saveFailed && (
-      <Toast show onClose={clearSaveFailed}>
-        <FormattedMessage {...messages.contentSaveFailed} />
-      </Toast>
-    )}
-    <ModalDialog.Footer className="shadow-sm">
-      <ActionRow>
-        <Button
-          aria-label={intl.formatMessage(messages.cancelButtonAriaLabel)}
-          variant="tertiary"
-          onClick={onCancel}
-        >
-          <FormattedMessage {...messages.cancelButtonLabel} />
-        </Button>
-        <Button
-          aria-label={intl.formatMessage(messages.saveButtonAriaLabel)}
-          onClick={onSave}
-          disabled={disableSave}
-        >
-          {disableSave
-            ? <Spinner animation="border" className="mr-3" />
-            : <FormattedMessage {...messages.saveButtonLabel} />}
-        </Button>
-      </ActionRow>
-    </ModalDialog.Footer>
-  </div>
-);
-
-EditorFooter.propTypes = {
-  clearSaveFailed: PropTypes.func.isRequired,
-  disableSave: PropTypes.bool.isRequired,
-  onCancel: PropTypes.func.isRequired,
-  onSave: PropTypes.func.isRequired,
-  saveFailed: PropTypes.bool.isRequired,
-  // injected
-  intl: intlShape.isRequired,
-};
-
-export const EditorFooterInternal = EditorFooter; // For testing only
-export default injectIntl(EditorFooter);
diff --git a/src/editors/containers/EditorContainer/components/EditorFooter/index.test.jsx b/src/editors/containers/EditorContainer/components/EditorFooter/index.test.jsx
deleted file mode 100644
index aaa78980a2..0000000000
--- a/src/editors/containers/EditorContainer/components/EditorFooter/index.test.jsx
+++ /dev/null
@@ -1,33 +0,0 @@
-import 'CourseAuthoring/editors/setupEditorTest';
-import React from 'react';
-import { shallow } from '@edx/react-unit-test-utils';
-
-import { formatMessage } from '../../../../testUtils';
-import { EditorFooterInternal as EditorFooter } from '.';
-
-jest.mock('../../hooks', () => ({
-  nullMethod: jest.fn().mockName('hooks.nullMethod'),
-}));
-
-describe('EditorFooter', () => {
-  const props = {
-    intl: { formatMessage },
-    disableSave: false,
-    onCancel: jest.fn().mockName('args.onCancel'),
-    onSave: jest.fn().mockName('args.onSave'),
-    saveFailed: false,
-  };
-  describe('render', () => {
-    test('snapshot: default args (disableSave: false, saveFailed: false)', () => {
-      expect(shallow(<EditorFooter {...props} />).snapshot).toMatchSnapshot();
-    });
-
-    test('snapshot: save disabled. Show button spinner', () => {
-      expect(shallow(<EditorFooter {...props} disableSave />).snapshot).toMatchSnapshot();
-    });
-
-    test('snapshot: save failed.  Show error message', () => {
-      expect(shallow(<EditorFooter {...props} saveFailed />).snapshot).toMatchSnapshot();
-    });
-  });
-});
diff --git a/src/editors/containers/EditorContainer/components/EditorFooter/messages.js b/src/editors/containers/EditorContainer/components/EditorFooter/messages.js
deleted file mode 100644
index ce7503ff14..0000000000
--- a/src/editors/containers/EditorContainer/components/EditorFooter/messages.js
+++ /dev/null
@@ -1,32 +0,0 @@
-import { defineMessages } from '@edx/frontend-platform/i18n';
-
-const messages = defineMessages({
-
-  contentSaveFailed: {
-    id: 'authoring.editorfooter.save.error',
-    defaultMessage: 'Error: Content save failed. Please check recent changes and try again later.',
-    description: 'Error message displayed when content fails to save.',
-  },
-  cancelButtonAriaLabel: {
-    id: 'authoring.editorfooter.cancelButton.ariaLabel',
-    defaultMessage: 'Discard changes and return to learning context',
-    description: 'Screen reader label for cancel button',
-  },
-  cancelButtonLabel: {
-    id: 'authoring.editorfooter.cancelButton.label',
-    defaultMessage: 'Cancel',
-    description: 'Label for cancel button',
-  },
-  saveButtonAriaLabel: {
-    id: 'authoring.editorfooter.savebutton.ariaLabel',
-    defaultMessage: 'Save changes and return to learning context',
-    description: 'Screen reader label for save button',
-  },
-  saveButtonLabel: {
-    id: 'authoring.editorfooter.savebutton.label',
-    defaultMessage: 'Save',
-    description: 'Label for Save button',
-  },
-});
-
-export default messages;
diff --git a/src/editors/containers/EditorContainer/hooks.test.jsx b/src/editors/containers/EditorContainer/hooks.test.jsx
index e73534f5b3..815a4cc12a 100644
--- a/src/editors/containers/EditorContainer/hooks.test.jsx
+++ b/src/editors/containers/EditorContainer/hooks.test.jsx
@@ -118,6 +118,7 @@ describe('EditorContainer hooks', () => {
             destination: reactRedux.useSelector(selectors.app.returnUrl),
             analyticsEvent: analyticsEvt.editorCancelClick,
             analytics: reactRedux.useSelector(selectors.app.analytics),
+            returnFunction: null,
           }),
         );
       });
diff --git a/src/editors/containers/EditorContainer/hooks.js b/src/editors/containers/EditorContainer/hooks.ts
similarity index 81%
rename from src/editors/containers/EditorContainer/hooks.js
rename to src/editors/containers/EditorContainer/hooks.ts
index 72b8a0e20f..935e3ad89d 100644
--- a/src/editors/containers/EditorContainer/hooks.js
+++ b/src/editors/containers/EditorContainer/hooks.ts
@@ -6,11 +6,6 @@ import { RequestKeys } from '../../data/constants/requests';
 import { selectors } from '../../data/redux';
 import { StrictDict } from '../../utils';
 import * as appHooks from '../../hooks';
-// This 'module' self-import hack enables mocking during tests.
-// See src/editors/decisions/0005-internal-editor-testability-decisions.md. The whole approach to how hooks are tested
-// should be re-thought and cleaned up to avoid this pattern.
-// eslint-disable-next-line import/no-self-import
-import * as module from './hooks';
 
 export const {
   clearSaveError,
@@ -47,7 +42,7 @@ export const handleSaveClicked = ({
 };
 
 export const cancelConfirmModalToggle = () => {
-  const [isCancelConfirmOpen, setIsOpen] = module.state.isCancelConfirmModalOpen(false);
+  const [isCancelConfirmOpen, setIsOpen] = state.isCancelConfirmModalOpen(false);
   return {
     isCancelConfirmOpen,
     openCancelConfirmModal: () => setIsOpen(true),
@@ -55,7 +50,13 @@ export const cancelConfirmModalToggle = () => {
   };
 };
 
-export const handleCancel = ({ onClose, returnFunction }) => {
+export const handleCancel = ({
+  onClose = null,
+  returnFunction = null,
+}: {
+  onClose?: (() => void) | null;
+  returnFunction?: (() => (result: any) => void) | null;
+}): ((result?: any) => void) => {
   if (onClose) {
     return onClose;
   }
diff --git a/src/editors/containers/EditorContainer/index.jsx b/src/editors/containers/EditorContainer/index.jsx
deleted file mode 100644
index 9cfd96888b..0000000000
--- a/src/editors/containers/EditorContainer/index.jsx
+++ /dev/null
@@ -1,104 +0,0 @@
-import React from 'react';
-import { useDispatch } from 'react-redux';
-import PropTypes from 'prop-types';
-
-import {
-  Icon, ModalDialog, IconButton, Button,
-} from '@openedx/paragon';
-import { Close } from '@openedx/paragon/icons';
-import { injectIntl, intlShape, FormattedMessage } from '@edx/frontend-platform/i18n';
-
-import BaseModal from '../../sharedComponents/BaseModal';
-import EditorFooter from './components/EditorFooter';
-import TitleHeader from './components/TitleHeader';
-import * as hooks from './hooks';
-import messages from './messages';
-import './index.scss';
-
-const EditorContainer = ({
-  children,
-  getContent,
-  onClose,
-  validateEntry,
-  returnFunction,
-  // injected
-  intl,
-}) => {
-  const dispatch = useDispatch();
-  const isInitialized = hooks.isInitialized();
-  const { isCancelConfirmOpen, openCancelConfirmModal, closeCancelConfirmModal } = hooks.cancelConfirmModalToggle();
-  const handleCancel = hooks.handleCancel({ onClose, returnFunction });
-  return (
-    <div
-      className="editor-container d-flex flex-column position-relative zindex-0"
-      style={{ minHeight: '100%' }}
-    >
-      <BaseModal
-        size="md"
-        confirmAction={(
-          <Button
-            variant="primary"
-            onClick={() => {
-              handleCancel();
-              if (returnFunction) {
-                closeCancelConfirmModal();
-              }
-            }}
-          >
-            <FormattedMessage {...messages.okButtonLabel} />
-          </Button>
-        )}
-        isOpen={isCancelConfirmOpen}
-        close={closeCancelConfirmModal}
-        title={intl.formatMessage(messages.cancelConfirmTitle)}
-      >
-        <FormattedMessage {...messages.cancelConfirmDescription} />
-      </BaseModal>
-      <ModalDialog.Header className="shadow-sm zindex-10">
-        <div className="d-flex flex-row justify-content-between">
-          <h2 className="h3 col pl-0">
-            <TitleHeader isInitialized={isInitialized} />
-          </h2>
-          <IconButton
-            src={Close}
-            iconAs={Icon}
-            onClick={openCancelConfirmModal}
-            alt={intl.formatMessage(messages.exitButtonAlt)}
-          />
-        </div>
-      </ModalDialog.Header>
-      <ModalDialog.Body className="pb-0 mb-6">
-        {isInitialized && children}
-      </ModalDialog.Body>
-      <EditorFooter
-        clearSaveFailed={hooks.clearSaveError({ dispatch })}
-        disableSave={!isInitialized}
-        onCancel={openCancelConfirmModal}
-        onSave={hooks.handleSaveClicked({
-          dispatch,
-          getContent,
-          validateEntry,
-          returnFunction,
-        })}
-        saveFailed={hooks.saveFailed()}
-      />
-    </div>
-  );
-};
-EditorContainer.defaultProps = {
-  onClose: null,
-  returnFunction: null,
-  validateEntry: null,
-};
-EditorContainer.propTypes = {
-  children: PropTypes.node.isRequired,
-  getContent: PropTypes.func.isRequired,
-  onClose: PropTypes.func,
-  returnFunction: PropTypes.func,
-  validateEntry: PropTypes.func,
-  // injected
-  intl: intlShape.isRequired,
-};
-
-export const EditorContainerInternal = EditorContainer; // For testing only
-export default injectIntl(EditorContainer);
diff --git a/src/editors/containers/EditorContainer/index.test.jsx b/src/editors/containers/EditorContainer/index.test.jsx
deleted file mode 100644
index 5360fdb7de..0000000000
--- a/src/editors/containers/EditorContainer/index.test.jsx
+++ /dev/null
@@ -1,68 +0,0 @@
-import 'CourseAuthoring/editors/setupEditorTest';
-import { shallow } from '@edx/react-unit-test-utils';
-import { useDispatch } from 'react-redux';
-
-import { EditorContainerInternal as EditorContainer } from '.';
-import * as hooks from './hooks';
-import { formatMessage } from '../../testUtils';
-
-const props = {
-  getContent: jest.fn().mockName('props.getContent'),
-  onClose: jest.fn().mockName('props.onClose'),
-  validateEntry: jest.fn().mockName('props.validateEntry'),
-  returnFunction: jest.fn().mockName('props.returnFunction'),
-  // inject
-  intl: { formatMessage },
-};
-
-jest.mock('./hooks', () => ({
-  clearSaveError: jest.fn().mockName('hooks.clearSaveError'),
-  isInitialized: jest.fn().mockReturnValue(true),
-  handleCancel: (args) => ({ handleCancel: args }),
-  handleSaveClicked: (args) => ({ handleSaveClicked: args }),
-  saveFailed: jest.fn().mockName('hooks.saveFailed'),
-  cancelConfirmModalToggle: jest.fn(() => ({
-    isCancelConfirmOpen: false,
-    openCancelConfirmModal: jest.fn().mockName('openCancelConfirmModal'),
-    closeCancelConfirmModal: jest.fn().mockName('closeCancelConfirmModal'),
-  })),
-}));
-
-let el;
-
-describe('EditorContainer component', () => {
-  describe('render', () => {
-    const testContent = (<h1>My test content</h1>);
-    test('snapshot: not initialized. disable save and pass to header', () => {
-      hooks.isInitialized.mockReturnValueOnce(false);
-      expect(
-        shallow(<EditorContainer {...props}>{testContent}</EditorContainer>).snapshot,
-      ).toMatchSnapshot();
-    });
-    test('snapshot: initialized. enable save and pass to header', () => {
-      expect(
-        shallow(<EditorContainer {...props}>{testContent}</EditorContainer>).snapshot,
-      ).toMatchSnapshot();
-    });
-    describe('behavior inspection', () => {
-      beforeEach(() => {
-        el = shallow(<EditorContainer {...props}>{testContent}</EditorContainer>);
-      });
-      test('save behavior is linked to footer onSave', () => {
-        const expected = hooks.handleSaveClicked({
-          dispatch: useDispatch(),
-          getContent: props.getContent,
-          validateEntry: props.validateEntry,
-          returnFunction: props.returnFunction,
-        });
-        expect(el.shallowWrapper.props.children[3]
-          .props.onSave).toEqual(expected);
-      });
-      test('behavior is linked to clearSaveError', () => {
-        const expected = hooks.clearSaveError({ dispatch: useDispatch() });
-        expect(el.shallowWrapper.props.children[3]
-          .props.clearSaveFailed).toEqual(expected);
-      });
-    });
-  });
-});
diff --git a/src/editors/containers/EditorContainer/index.test.tsx b/src/editors/containers/EditorContainer/index.test.tsx
new file mode 100644
index 0000000000..2d63041341
--- /dev/null
+++ b/src/editors/containers/EditorContainer/index.test.tsx
@@ -0,0 +1,97 @@
+import { snakeCaseObject } from '@edx/frontend-platform';
+import {
+  render,
+  screen,
+  initializeMocks,
+  fireEvent,
+  waitFor,
+} from '../../../testUtils';
+import editorCmsApi from '../../data/services/cms/api';
+
+import EditorPage from '../../EditorPage';
+
+// Mock this plugins component:
+jest.mock('frontend-components-tinymce-advanced-plugins', () => ({ a11ycheckerCss: '' }));
+// Always mock out the "fetch course images" endpoint:
+jest.spyOn(editorCmsApi, 'fetchImages').mockImplementation(async () => ( // eslint-disable-next-line
+  { data: { assets: [], start: 0, end: 0, page: 0, pageSize: 50, totalCount: 0 } }
+));
+// Mock out the 'get ancestors' API:
+jest.spyOn(editorCmsApi, 'fetchByUnitId').mockImplementation(async () => ({
+  status: 200,
+  data: {
+    ancestors: [{
+      id: 'block-v1:Org+TS100+24+type@vertical+block@parent',
+      display_name: 'You-Knit? The Test Unit',
+      category: 'vertical',
+      has_children: true,
+    }],
+  },
+}));
+
+const defaultPropsHtml = {
+  blockId: 'block-v1:Org+TS100+24+type@html+block@123456html',
+  blockType: 'html',
+  courseId: 'course-v1:Org+TS100+24',
+  lmsEndpointUrl: 'http://lms.test.none/',
+  studioEndpointUrl: 'http://cms.test.none/',
+  onClose: jest.fn(),
+  fullScreen: false,
+};
+const fieldsHtml = {
+  displayName: 'Introduction to Testing',
+  data: '<p>This is a text component which uses <strong>HTML</strong>.</p>',
+  metadata: { displayName: 'Introduction to Testing' },
+};
+
+describe('EditorContainer', () => {
+  beforeEach(() => {
+    initializeMocks();
+  });
+
+  test('it displays a confirmation dialog when closing the editor modal', async () => {
+    jest.spyOn(editorCmsApi, 'fetchBlockById').mockImplementationOnce(async () => (
+      { status: 200, data: snakeCaseObject(fieldsHtml) }
+    ));
+
+    render(<EditorPage {...defaultPropsHtml} />);
+
+    // Then the editor should open
+    expect(await screen.findByRole('heading', { name: /Introduction to Testing/ })).toBeInTheDocument();
+
+    // Assert the "are you sure?" message isn't visible yet
+    const confirmMessage = /Are you sure you want to exit the editor/;
+    expect(screen.queryByText(confirmMessage)).not.toBeInTheDocument();
+
+    // Find and click the close button
+    const closeButton = await screen.findByRole('button', { name: 'Exit the editor' });
+    fireEvent.click(closeButton);
+    // Now we should see the confirmation message:
+    expect(await screen.findByText(confirmMessage)).toBeInTheDocument();
+
+    expect(defaultPropsHtml.onClose).not.toHaveBeenCalled();
+    // And can confirm the cancelation:
+    const confirmButton = await screen.findByRole('button', { name: 'OK' });
+    fireEvent.click(confirmButton);
+    expect(defaultPropsHtml.onClose).toHaveBeenCalled();
+  });
+
+  test('it disables the save button until the fields have been loaded', async () => {
+    // Mock that loading the block data has begun but not completed yet:
+    let resolver: (result: { data: any }) => void;
+    jest.spyOn(editorCmsApi, 'fetchBlockById').mockImplementationOnce(() => new Promise((r) => { resolver = r; }));
+
+    render(<EditorPage {...defaultPropsHtml} />);
+
+    // Then the editor should open. The "Save" button should be disabled
+    const saveButton = await screen.findByRole('button', { name: /Save changes and return/ });
+    expect(saveButton).toBeDisabled();
+
+    // Now complete the loading of the data:
+    await waitFor(() => expect(resolver).not.toBeUndefined());
+    resolver!({ data: snakeCaseObject(fieldsHtml) });
+
+    // Now the save button should be active:
+    await waitFor(() => expect(saveButton).not.toBeDisabled());
+  });
+});
diff --git a/src/editors/containers/EditorContainer/index.tsx b/src/editors/containers/EditorContainer/index.tsx
new file mode 100644
index 0000000000..3414680b58
--- /dev/null
+++ b/src/editors/containers/EditorContainer/index.tsx
@@ -0,0 +1,158 @@
+import React from 'react';
+import { useDispatch } from 'react-redux';
+
+import {
+  ActionRow,
+  Button,
+  Icon,
+  IconButton,
+  ModalDialog,
+  Spinner,
+  Toast,
+} from '@openedx/paragon';
+import { Close } from '@openedx/paragon/icons';
+import { useIntl, FormattedMessage } from '@edx/frontend-platform/i18n';
+
+import { EditorComponent } from '../../EditorComponent';
+import { useEditorContext } from '../../EditorContext';
+import BaseModal from '../../sharedComponents/BaseModal';
+import TitleHeader from './components/TitleHeader';
+import * as hooks from './hooks';
+import messages from './messages';
+import './index.scss';
+
+interface WrapperProps {
+  children: React.ReactNode;
+}
+
+export const EditorModalWrapper: React.FC<WrapperProps & { onClose: () => void }> = ({ children, onClose }) => {
+  const { fullScreen } = useEditorContext();
+  const intl = useIntl();
+  if (fullScreen) {
+    return (
+      <div
+        className="editor-container d-flex flex-column position-relative zindex-0"
+        style={{ minHeight: '100%' }}
+      >
+        {children}
+      </div>
+    );
+  }
+  const title = intl.formatMessage(messages.modalTitle);
+  return (
+    <ModalDialog isOpen size="xl" isOverflowVisible={false} onClose={onClose} title={title}>{children}</ModalDialog>
+  );
+};
+
+export const EditorModalBody: React.FC<WrapperProps> = ({ children }) => {
+  const { fullScreen } = useEditorContext();
+  return <ModalDialog.Body className={fullScreen ? 'pb-6' : 'pb-0'}>{ children }</ModalDialog.Body>;
+};
+
+export const FooterWrapper: React.FC<WrapperProps> = ({ children }) => {
+  const { fullScreen } = useEditorContext();
+  if (fullScreen) {
+    return <div className="editor-footer fixed-bottom">{children}</div>;
+  }
+  // eslint-disable-next-line react/jsx-no-useless-fragment
+  return <>{ children }</>;
+};
+
+interface Props extends EditorComponent {
+  children: React.ReactNode;
+  getContent: Function;
+  validateEntry?: Function | null;
+}
+
+const EditorContainer: React.FC<Props> = ({
+  children,
+  getContent,
+  onClose = null,
+  validateEntry = null,
+  returnFunction = null,
+}) => {
+  const intl = useIntl();
+  const dispatch = useDispatch();
+  const isInitialized = hooks.isInitialized();
+  const { isCancelConfirmOpen, openCancelConfirmModal, closeCancelConfirmModal } = hooks.cancelConfirmModalToggle();
+  const handleCancel = hooks.handleCancel({ onClose, returnFunction });
+  const disableSave = !isInitialized;
+  const saveFailed = hooks.saveFailed();
+  const clearSaveFailed = hooks.clearSaveError({ dispatch });
+  const onSave = hooks.handleSaveClicked({
+    dispatch,
+    getContent,
+    validateEntry,
+    returnFunction,
+  });
+  return (
+    <EditorModalWrapper onClose={openCancelConfirmModal}>
+      {saveFailed && (
+        <Toast show onClose={clearSaveFailed}>
+          <FormattedMessage {...messages.contentSaveFailed} />
+        </Toast>
+      )}
+      <BaseModal
+        size="md"
+        confirmAction={(
+          <Button
+            variant="primary"
+            onClick={() => {
+              handleCancel();
+              if (returnFunction) {
+                closeCancelConfirmModal();
+              }
+            }}
+          >
+            <FormattedMessage {...messages.okButtonLabel} />
+          </Button>
+        )}
+        isOpen={isCancelConfirmOpen}
+        close={closeCancelConfirmModal}
+        title={intl.formatMessage(messages.cancelConfirmTitle)}
+      >
+        <FormattedMessage {...messages.cancelConfirmDescription} />
+      </BaseModal>
+      <ModalDialog.Header className="shadow-sm zindex-10">
+        <div className="d-flex flex-row justify-content-between">
+          <h2 className="h3 col pl-0">
+            <TitleHeader isInitialized={isInitialized} />
+          </h2>
+          <IconButton
+            src={Close}
+            iconAs={Icon}
+            onClick={openCancelConfirmModal}
+            alt={intl.formatMessage(messages.exitButtonAlt)}
+          />
+        </div>
+      </ModalDialog.Header>
+      <EditorModalBody>
+        {isInitialized && children}
+      </EditorModalBody>
+      <FooterWrapper>
+        <ModalDialog.Footer className="shadow-sm">
+          <ActionRow>
+            <Button
+              aria-label={intl.formatMessage(messages.cancelButtonAriaLabel)}
+              variant="tertiary"
+              onClick={openCancelConfirmModal}
+            >
+              <FormattedMessage {...messages.cancelButtonLabel} />
+            </Button>
+            <Button
+              aria-label={intl.formatMessage(messages.saveButtonAriaLabel)}
+              onClick={onSave}
+              disabled={disableSave}
+            >
+              {disableSave
+                ? <Spinner animation="border" className="mr-3" />
+                : <FormattedMessage {...messages.saveButtonLabel} />}
+            </Button>
+          </ActionRow>
+        </ModalDialog.Footer>
+      </FooterWrapper>
+    </EditorModalWrapper>
+  );
+};
+
+export default EditorContainer;
diff --git a/src/editors/containers/EditorContainer/messages.ts b/src/editors/containers/EditorContainer/messages.ts
index a6f1754fb2..55b4259ca9 100644
--- a/src/editors/containers/EditorContainer/messages.ts
+++ b/src/editors/containers/EditorContainer/messages.ts
@@ -22,6 +22,36 @@ const messages = defineMessages({
     defaultMessage: 'OK',
     description: 'Label for OK button',
   },
+  modalTitle: {
+    id: 'authoring.editorContainer.accessibleTitle',
+    defaultMessage: 'Editor Dialog',
+    description: 'Text that labels the the editor modal dialog for non-visual users',
+  },
+  contentSaveFailed: {
+    id: 'authoring.editorfooter.save.error',
+    defaultMessage: 'Error: Content save failed. Please check recent changes and try again later.',
+    description: 'Error message displayed when content fails to save.',
+  },
+  cancelButtonAriaLabel: {
+    id: 'authoring.editorfooter.cancelButton.ariaLabel',
+    defaultMessage: 'Discard changes and return to learning context',
+    description: 'Screen reader label for cancel button',
+  },
+  cancelButtonLabel: {
+    id: 'authoring.editorfooter.cancelButton.label',
+    defaultMessage: 'Cancel',
+    description: 'Label for cancel button',
+  },
+  saveButtonAriaLabel: {
+    id: 'authoring.editorfooter.savebutton.ariaLabel',
+    defaultMessage: 'Save changes and return to learning context',
+    description: 'Screen reader label for save button',
+  },
+  saveButtonLabel: {
+    id: 'authoring.editorfooter.savebutton.label',
+    defaultMessage: 'Save',
+    description: 'Label for Save button',
+  },
 });
 
 export default messages;
diff --git a/src/editors/containers/ProblemEditor/components/EditProblemView/__snapshots__/index.test.jsx.snap b/src/editors/containers/ProblemEditor/components/EditProblemView/__snapshots__/index.test.jsx.snap
index 24c6543af9..428feabce6 100644
--- a/src/editors/containers/ProblemEditor/components/EditProblemView/__snapshots__/index.test.jsx.snap
+++ b/src/editors/containers/ProblemEditor/components/EditProblemView/__snapshots__/index.test.jsx.snap
@@ -1,7 +1,7 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`EditorProblemView component renders raw editor 1`] = `
-<injectIntl(ShimmedIntlComponent)
+<EditorContainer
   getContent={[Function]}
   returnFunction={null}
 >
@@ -66,11 +66,11 @@ exports[`EditorProblemView component renders raw editor 1`] = `
       />
     </span>
   </div>
-</injectIntl(ShimmedIntlComponent)>
+</EditorContainer>
 `;
 
 exports[`EditorProblemView component renders simple view 1`] = `
-<injectIntl(ShimmedIntlComponent)
+<EditorContainer
   getContent={[Function]}
   returnFunction={null}
 >
@@ -139,5 +139,5 @@ exports[`EditorProblemView component renders simple view 1`] = `
       />
     </span>
   </div>
-</injectIntl(ShimmedIntlComponent)>
+</EditorContainer>
 `;
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/SelectTypeFooter.jsx b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/SelectTypeFooter.jsx
deleted file mode 100644
index cd41940bb3..0000000000
--- a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/SelectTypeFooter.jsx
+++ /dev/null
@@ -1,63 +0,0 @@
-import React from 'react';
-import PropTypes from 'prop-types';
-import { useDispatch, useSelector } from 'react-redux';
-import { FormattedMessage, useIntl } from '@edx/frontend-platform/i18n';
-import {
-  ActionRow,
-  Button,
-  ModalDialog,
-} from '@openedx/paragon';
-import messages from './messages';
-import * as hooks from '../hooks';
-
-import { actions, selectors } from '../../../../../data/redux';
-
-const SelectTypeFooter = ({
-  onCancel,
-  selected,
-}) => {
-  const intl = useIntl();
-  const defaultSettings = useSelector(selectors.problem.defaultSettings);
-  const dispatch = useDispatch();
-  const updateField = React.useCallback((data) => dispatch(actions.problem.updateField(data)), [dispatch]);
-  const setBlockTitle = React.useCallback((title) => dispatch(actions.app.setBlockTitle(title)), [dispatch]);
-  return (
-    <div className="editor-footer fixed-bottom">
-      <ModalDialog.Footer className="border-top-0">
-        <ActionRow>
-          <ActionRow.Spacer />
-          <Button
-            aria-label={intl.formatMessage(messages.cancelButtonAriaLabel)}
-            variant="tertiary"
-            onClick={onCancel}
-          >
-            <FormattedMessage {...messages.cancelButtonLabel} />
-          </Button>
-          <Button
-            aria-label={intl.formatMessage(messages.selectButtonAriaLabel)}
-            onClick={hooks.onSelect({
-              selected,
-              updateField,
-              setBlockTitle,
-              defaultSettings,
-            })}
-            disabled={!selected}
-          >
-            <FormattedMessage {...messages.selectButtonLabel} />
-          </Button>
-        </ActionRow>
-      </ModalDialog.Footer>
-    </div>
-  );
-};
-
-SelectTypeFooter.defaultProps = {
-  selected: null,
-};
-
-SelectTypeFooter.propTypes = {
-  onCancel: PropTypes.func.isRequired,
-  selected: PropTypes.string,
-};
-
-export default SelectTypeFooter;
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/SelectTypeFooter.test.jsx b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/SelectTypeFooter.test.jsx
deleted file mode 100644
index d0795c36ba..0000000000
--- a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/SelectTypeFooter.test.jsx
+++ /dev/null
@@ -1,45 +0,0 @@
-import 'CourseAuthoring/editors/setupEditorTest';
-import { shallow } from '@edx/react-unit-test-utils';
-
-import { Button } from '@openedx/paragon';
-import { formatMessage } from '../../../../../testUtils';
-import SelectTypeFooter from './SelectTypeFooter';
-import * as hooks from '../hooks';
-
-jest.mock('../hooks', () => ({
-  onSelect: jest.fn().mockName('onSelect'),
-}));
-
-describe('SelectTypeFooter', () => {
-  const props = {
-    onCancel: jest.fn().mockName('onCancel'),
-    selected: null,
-    // redux
-    defaultSettings: {},
-    updateField: jest.fn().mockName('UpdateField'),
-    // inject
-    intl: { formatMessage },
-  };
-
-  test('snapshot', () => {
-    expect(shallow(<SelectTypeFooter {...props} />).snapshot).toMatchSnapshot();
-  });
-
-  describe('behavior', () => {
-    let el;
-    beforeEach(() => {
-      el = shallow(<SelectTypeFooter {...props} />);
-    });
-    test('close behavior is linked to modal onCancel', () => {
-      const expected = props.onCancel;
-      expect(el.instance.findByType(Button)[0].props.onClick)
-        .toEqual(expected);
-    });
-    test('select behavior is linked to modal onSelect', () => {
-      const expected = hooks.onSelect(props.selected, props.updateField);
-      const button = el.instance.findByType(Button);
-      expect(button[button.length - 1].props.onClick)
-        .toEqual(expected);
-    });
-  });
-});
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/SelectTypeFooter.test.jsx.snap b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/SelectTypeFooter.test.jsx.snap
deleted file mode 100644
index 5d136ff50b..0000000000
--- a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/SelectTypeFooter.test.jsx.snap
+++ /dev/null
@@ -1,36 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`SelectTypeFooter snapshot 1`] = `
-<div
-  className="editor-footer fixed-bottom"
->
-  <ModalDialog.Footer
-    className="border-top-0"
-  >
-    <ActionRow>
-      <ActionRow.Spacer />
-      <Button
-        aria-label="Cancel"
-        onClick={[MockFunction onCancel]}
-        variant="tertiary"
-      >
-        <FormattedMessage
-          defaultMessage="Cancel"
-          description="Label for cancel button."
-          id="authoring.problemeditor.selecttype.cancelButton.label"
-        />
-      </Button>
-      <Button
-        aria-label="Select"
-        disabled={true}
-      >
-        <FormattedMessage
-          defaultMessage="Select"
-          description="Label for select button."
-          id="authoring.problemeditor.selecttype.selectButton.label"
-        />
-      </Button>
-    </ActionRow>
-  </ModalDialog.Footer>
-</div>
-`;
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/index.test.jsx.snap b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/index.test.jsx.snap
deleted file mode 100644
index fb228f3205..0000000000
--- a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/index.test.jsx.snap
+++ /dev/null
@@ -1,38 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`SelectTypeWrapper snapshot 1`] = `
-<div
-  className="position-relative zindex-0"
->
-  <ModalDialog.Header
-    className="shadow-sm zindex-10"
-  >
-    <ModalDialog.Title>
-      <FormattedMessage
-        defaultMessage="Select problem type"
-        description="Title for select problem type modal"
-        id="authoring.problemEditor.selectType.title"
-      />
-      <div
-        className="pgn__modal-close-container"
-      >
-        <IconButton
-          alt="Exit the editor"
-          iconAs="Icon"
-          src={[MockFunction icons.Close]}
-        />
-      </div>
-    </ModalDialog.Title>
-  </ModalDialog.Header>
-  <ModalDialog.Body
-    className="pb-6"
-  >
-    <h1>
-      test child
-    </h1>
-  </ModalDialog.Body>
-  <SelectTypeFooter
-    selected="iMAsElecTedValUE"
-  />
-</div>
-`;
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/index.test.tsx.snap b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/index.test.tsx.snap
new file mode 100644
index 0000000000..44c6994873
--- /dev/null
+++ b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/__snapshots__/index.test.tsx.snap
@@ -0,0 +1,61 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`SelectTypeWrapper snapshot 1`] = `
+<EditorModalWrapper>
+  <ModalDialog.Header
+    className="shadow-sm zindex-10"
+  >
+    <ModalDialog.Title>
+      <FormattedMessage
+        defaultMessage="Select problem type"
+        description="Title for select problem type modal"
+        id="authoring.problemEditor.selectType.title"
+      />
+      <div
+        className="pgn__modal-close-container"
+      >
+        <IconButton
+          alt="Exit the editor"
+          iconAs="Icon"
+          src={[MockFunction icons.Close]}
+        />
+      </div>
+    </ModalDialog.Title>
+  </ModalDialog.Header>
+  <EditorModalBody>
+    <h1>
+      test child
+    </h1>
+  </EditorModalBody>
+  <FooterWrapper>
+    <ModalDialog.Footer
+      className="border-top-0"
+    >
+      <ActionRow>
+        <ActionRow.Spacer />
+        <Button
+          aria-label="Cancel"
+          variant="tertiary"
+        >
+          <FormattedMessage
+            defaultMessage="Cancel"
+            description="Label for cancel button."
+            id="authoring.problemeditor.selecttype.cancelButton.label"
+          />
+        </Button>
+        <Button
+          aria-label="Select"
+          disabled={false}
+          onClick={[Function]}
+        >
+          <FormattedMessage
+            defaultMessage="Select"
+            description="Label for select button."
+            id="authoring.problemeditor.selecttype.selectButton.label"
+          />
+        </Button>
+      </ActionRow>
+    </ModalDialog.Footer>
+  </FooterWrapper>
+</EditorModalWrapper>
+`;
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.jsx b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.jsx
deleted file mode 100644
index e452967172..0000000000
--- a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.jsx
+++ /dev/null
@@ -1,57 +0,0 @@
-import React from 'react';
-import PropTypes from 'prop-types';
-import { FormattedMessage, useIntl } from '@edx/frontend-platform/i18n';
-import { Icon, ModalDialog, IconButton } from '@openedx/paragon';
-import { Close } from '@openedx/paragon/icons';
-import SelectTypeFooter from './SelectTypeFooter';
-
-import * as hooks from '../../../../EditorContainer/hooks';
-import ecMessages from '../../../../EditorContainer/messages';
-import messages from './messages';
-
-const SelectTypeWrapper = ({
-  children,
-  onClose,
-  selected,
-}) => {
-  const handleCancel = hooks.handleCancel({ onClose });
-  const intl = useIntl();
-
-  return (
-    <div
-      className="position-relative zindex-0"
-    >
-      <ModalDialog.Header className="shadow-sm zindex-10">
-        <ModalDialog.Title>
-          <FormattedMessage {...messages.selectTypeTitle} />
-          <div className="pgn__modal-close-container">
-            <IconButton
-              src={Close}
-              iconAs={Icon}
-              onClick={handleCancel}
-              alt={intl.formatMessage(ecMessages.exitButtonAlt)}
-            />
-          </div>
-        </ModalDialog.Title>
-      </ModalDialog.Header>
-      <ModalDialog.Body className="pb-6">
-        {children}
-      </ModalDialog.Body>
-      <SelectTypeFooter
-        selected={selected}
-        onCancel={handleCancel}
-      />
-    </div>
-  );
-};
-
-SelectTypeWrapper.defaultProps = {
-  onClose: null,
-};
-SelectTypeWrapper.propTypes = {
-  selected: PropTypes.string.isRequired,
-  children: PropTypes.node.isRequired,
-  onClose: PropTypes.func,
-};
-
-export default SelectTypeWrapper;
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.test.jsx b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.test.tsx
similarity index 100%
rename from src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.test.jsx
rename to src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.test.tsx
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.tsx b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.tsx
new file mode 100644
index 0000000000..5df0c0be09
--- /dev/null
+++ b/src/editors/containers/ProblemEditor/components/SelectTypeModal/SelectTypeWrapper/index.tsx
@@ -0,0 +1,85 @@
+import React from 'react';
+import { FormattedMessage, useIntl } from '@edx/frontend-platform/i18n';
+import { useDispatch, useSelector } from 'react-redux';
+import {
+  ActionRow,
+  Button,
+  Icon,
+  ModalDialog,
+  IconButton,
+} from '@openedx/paragon';
+import { Close } from '@openedx/paragon/icons';
+
+import { EditorModalBody, EditorModalWrapper, FooterWrapper } from '../../../../EditorContainer';
+import { actions, selectors } from '../../../../../data/redux';
+import * as containerHooks from '../../../../EditorContainer/hooks';
+import * as hooks from '../hooks';
+import ecMessages from '../../../../EditorContainer/messages';
+import messages from './messages';
+
+interface Props {
+  selected: string;
+  onClose: (() => void) | null;
+}
+
+const SelectTypeWrapper: React.FC<Props> = ({
+  children,
+  onClose = null,
+  selected,
+}) => {
+  const handleCancel = containerHooks.handleCancel({ onClose });
+  const intl = useIntl();
+  const defaultSettings = useSelector(selectors.problem.defaultSettings);
+  const dispatch = useDispatch();
+  const updateField = React.useCallback((data) => dispatch(actions.problem.updateField(data)), [dispatch]);
+  const setBlockTitle = React.useCallback((title) => dispatch(actions.app.setBlockTitle(title)), [dispatch]);
+
+  return (
+    <EditorModalWrapper onClose={handleCancel}>
+      <ModalDialog.Header className="shadow-sm zindex-10">
+        <ModalDialog.Title>
+          <FormattedMessage {...messages.selectTypeTitle} />
+          <div className="pgn__modal-close-container">
+            <IconButton
+              src={Close}
+              iconAs={Icon}
+              onClick={handleCancel}
+              alt={intl.formatMessage(ecMessages.exitButtonAlt)}
+            />
+          </div>
+        </ModalDialog.Title>
+      </ModalDialog.Header>
+      <EditorModalBody>
+        {children}
+      </EditorModalBody>
+      <FooterWrapper>
+        <ModalDialog.Footer className="border-top-0">
+          <ActionRow>
+            <ActionRow.Spacer />
+            <Button
+              aria-label={intl.formatMessage(messages.cancelButtonAriaLabel)}
+              variant="tertiary"
+              onClick={handleCancel}
+            >
+              <FormattedMessage {...messages.cancelButtonLabel} />
+            </Button>
+            <Button
+              aria-label={intl.formatMessage(messages.selectButtonAriaLabel)}
+              onClick={hooks.onSelect({
+                selected,
+                updateField,
+                setBlockTitle,
+                defaultSettings,
+              })}
+              disabled={!selected}
+            >
+              <FormattedMessage {...messages.selectButtonLabel} />
+            </Button>
+          </ActionRow>
+        </ModalDialog.Footer>
+      </FooterWrapper>
+    </EditorModalWrapper>
+  );
+};
+
+export default SelectTypeWrapper;
diff --git a/src/editors/containers/ProblemEditor/components/SelectTypeModal/index.test.tsx b/src/editors/containers/ProblemEditor/components/SelectTypeModal/index.test.tsx
index 9be7578c5f..ce2fbd7037 100644
--- a/src/editors/containers/ProblemEditor/components/SelectTypeModal/index.test.tsx
+++ b/src/editors/containers/ProblemEditor/components/SelectTypeModal/index.test.tsx
@@ -6,6 +6,7 @@ import {
   initializeMocks,
 } from '../../../../../testUtils';
 import editorStore from '../../../../data/store';
+import { EditorContextProvider } from '../../../../EditorContext';
 import * as hooks from './hooks';
 import SelectTypeModal from '.';
 
@@ -18,7 +19,13 @@ describe('SelectTypeModal', () => {
     const mockSelect = jest.fn();
     jest.spyOn(hooks, 'onSelect').mockImplementation(mockSelect);
     // This is a new-style test, unlike most of the old snapshot-based editor tests.
-    render(<Provider store={editorStore}><SelectTypeModal onClose={mockClose} /></Provider>);
+    render(
+      <EditorContextProvider fullScreen={false} learningContextId="course-v1:Org+COURSE+RUN">
+        <Provider store={editorStore}>
+          <SelectTypeModal onClose={mockClose} />
+        </Provider>
+      </EditorContextProvider>,
+    );
 
     // First we see the menu of problem types:
     expect(await screen.findByRole('button', { name: 'Numerical input' })).toBeInTheDocument();
diff --git a/src/editors/data/services/cms/api.ts b/src/editors/data/services/cms/api.ts
index 673309bb00..d40c9d5f36 100644
--- a/src/editors/data/services/cms/api.ts
+++ b/src/editors/data/services/cms/api.ts
@@ -19,6 +19,21 @@ interface AssetResponse {
   assets: Record<string, string>[]; // In the raw response here, these are NOT camel-cased yet.
 }
 
+type FieldsResponse = {
+  display_name: string; // In the raw response here, these are NOT camel-cased yet.
+  data: any;
+  metadata: Record<string, any>;
+} & Record<string, any>; // In courses (but not in libraries), there are many other fields returned here.
+
+interface AncestorsResponse {
+  ancestors: {
+    id: string;
+    display_name: string; // In the raw response here, these are NOT camel-cased yet.
+    category: string;
+    has_children: boolean;
+  }[];
+}
+
 export const loadImage = (imageData) => ({
   ...imageData,
   dateAdded: new Date(imageData.dateAdded.replace(' at', '')).getTime(),
@@ -89,10 +104,11 @@ export const processLicense = (licenseType, licenseDetails) => {
 };
 
 export const apiMethods = {
-  fetchBlockById: ({ blockId, studioEndpointUrl }) => get(
+  fetchBlockById: ({ blockId, studioEndpointUrl }): Promise<{ data: FieldsResponse }> => get(
     urls.block({ blockId, studioEndpointUrl }),
   ),
-  fetchByUnitId: ({ blockId, studioEndpointUrl }) => get(
+  /** A better name for this would be 'get ancestors of block' */
+  fetchByUnitId: ({ blockId, studioEndpointUrl }): Promise<{ data: AncestorsResponse }> => get(
     urls.blockAncestor({ studioEndpointUrl, blockId }),
     fetchByUnitIdOptions,
   ),
diff --git a/src/editors/hooks.js b/src/editors/hooks.ts
similarity index 77%
rename from src/editors/hooks.js
rename to src/editors/hooks.ts
index c0d1b70a87..d2a7403d87 100644
--- a/src/editors/hooks.js
+++ b/src/editors/hooks.ts
@@ -4,11 +4,6 @@ import { sendTrackEvent } from '@edx/frontend-platform/analytics';
 import analyticsEvt from './data/constants/analyticsEvt';
 
 import { actions, thunkActions } from './data/redux';
-// This 'module' self-import hack enables mocking during tests.
-// See src/editors/decisions/0005-internal-editor-testability-decisions.md. The whole approach to how hooks are tested
-// should be re-thought and cleaned up to avoid this pattern.
-// eslint-disable-next-line import/no-self-import
-import * as module from './hooks';
 import { RequestKeys } from './data/constants/requests';
 
 // eslint-disable-next-line react-hooks/rules-of-hooks
@@ -17,7 +12,7 @@ export const initializeApp = ({ dispatch, data }) => useEffect(
   [data],
 );
 
-export const navigateTo = (destination) => {
+export const navigateTo = (destination: string | URL) => {
   window.location.assign(destination);
 };
 
@@ -34,7 +29,7 @@ export const navigateCallback = ({
     returnFunction()(response);
     return;
   }
-  module.navigateTo(destination);
+  navigateTo(destination);
 };
 
 export const nullMethod = () => ({});
@@ -61,7 +56,7 @@ export const saveBlock = ({
   if (attemptSave) {
     dispatch(thunkActions.app.saveBlock(
       content,
-      module.navigateCallback({
+      navigateCallback({
         destination,
         analyticsEvent: analyticsEvt.editorSaveClick,
         analytics,
diff --git a/src/editors/messages.js b/src/editors/messages.ts
similarity index 100%
rename from src/editors/messages.js
rename to src/editors/messages.ts
diff --git a/src/library-authoring/LibraryAuthoringPage.test.tsx b/src/library-authoring/LibraryAuthoringPage.test.tsx
index 9fc69521a5..bd0d911ed5 100644
--- a/src/library-authoring/LibraryAuthoringPage.test.tsx
+++ b/src/library-authoring/LibraryAuthoringPage.test.tsx
@@ -80,6 +80,7 @@ describe('<LibraryAuthoringPage />', () => {
     initializeMocks();
 
     // The Meilisearch client-side API uses fetch, not Axios.
+    fetchMock.mockReset();
     fetchMock.post(searchEndpoint, (_url, req) => {
       const requestData = JSON.parse(req.body?.toString() ?? '');
       const query = requestData?.queries[0]?.q ?? '';
@@ -94,11 +95,6 @@ describe('<LibraryAuthoringPage />', () => {
     });
   });
 
-  afterEach(() => {
-    jest.clearAllMocks();
-    fetchMock.mockReset();
-  });
-
   const renderLibraryPage = async () => {
     render(<LibraryLayout />, { path, params: { libraryId: mockContentLibrary.libraryId } });
 
diff --git a/src/library-authoring/LibraryLayout.tsx b/src/library-authoring/LibraryLayout.tsx
index 56718cc5ef..78d60674ae 100644
--- a/src/library-authoring/LibraryLayout.tsx
+++ b/src/library-authoring/LibraryLayout.tsx
@@ -1,70 +1,26 @@
-import React from 'react';
 import {
   Route,
   Routes,
-  useNavigate,
   useParams,
 } from 'react-router-dom';
-import { PageWrap } from '@edx/frontend-platform/react';
-import { useQueryClient } from '@tanstack/react-query';
 
-import EditorContainer from '../editors/EditorContainer';
 import LibraryAuthoringPage from './LibraryAuthoringPage';
 import { LibraryProvider } from './common/context';
 import { CreateCollectionModal } from './create-collection';
-import { invalidateComponentData } from './data/apiHooks';
 import LibraryCollectionPage from './collections/LibraryCollectionPage';
+import { ComponentEditorModal } from './components/ComponentEditorModal';
 
 const LibraryLayout = () => {
   const { libraryId } = useParams();
-  const queryClient = useQueryClient();
 
   if (libraryId === undefined) {
     // istanbul ignore next - This shouldn't be possible; it's just here to satisfy the type checker.
     throw new Error('Error: route is missing libraryId.');
   }
 
-  const navigate = useNavigate();
-  const goBack = React.useCallback((prevPath?: string) => {
-    if (prevPath) {
-      // Redirects back to the previous route like collection page or library page
-      navigate(prevPath);
-    } else {
-      // Go back to the library
-      navigate(`/library/${libraryId}`);
-    }
-  }, []);
-
-  const returnFunction = React.useCallback((prevPath?: string) => {
-    // When changes are cancelled, either onClose (goBack) or this returnFunction will be called.
-    // When changes are saved, this returnFunction is called.
-    goBack(prevPath);
-    return (args) => {
-      if (args === undefined) {
-        return; // Do nothing - the user cancelled the changes
-      }
-      const { id: usageKey } = args;
-      // invalidate any queries that involve this XBlock:
-      invalidateComponentData(queryClient, libraryId, usageKey);
-    };
-  }, [goBack]);
-
   return (
     <LibraryProvider libraryId={libraryId}>
       <Routes>
-        {/*
-          TODO: we should be opening this editor as a modal, not making it a separate page/URL.
-          That will be a much nicer UX because users can just close the modal and be on the same page they were already
-          on, instead of always getting sent back to the library home.
-        */}
-        <Route
-          path="editor/:blockType/:blockId?"
-          element={(
-            <PageWrap>
-              <EditorContainer learningContextId={libraryId} onClose={goBack} returnFunction={returnFunction} />
-            </PageWrap>
-          )}
-        />
         <Route
           path="collection/:collectionId"
           element={<LibraryCollectionPage />}
@@ -75,6 +31,7 @@ const LibraryLayout = () => {
         />
       </Routes>
       <CreateCollectionModal />
+      <ComponentEditorModal />
     </LibraryProvider>
   );
 };
diff --git a/src/library-authoring/add-content/AddContentContainer.tsx b/src/library-authoring/add-content/AddContentContainer.tsx
index fe88ba0cdc..d37fd75f05 100644
--- a/src/library-authoring/add-content/AddContentContainer.tsx
+++ b/src/library-authoring/add-content/AddContentContainer.tsx
@@ -16,14 +16,14 @@ import {
   ContentPaste,
 } from '@openedx/paragon/icons';
 import { v4 as uuid4 } from 'uuid';
-import { useLocation, useNavigate, useParams } from 'react-router-dom';
+import { useParams } from 'react-router-dom';
 
 import { ToastContext } from '../../generic/toast-context';
 import { useCopyToClipboard } from '../../generic/clipboard';
 import { getCanEdit } from '../../course-unit/data/selectors';
 import { useCreateLibraryBlock, useLibraryPasteClipboard, useUpdateCollectionComponents } from '../data/apiHooks';
-import { getEditUrl } from '../components/utils';
 import { useLibraryContext } from '../common/context';
+import { canEditComponent } from '../components/ComponentEditorModal';
 
 import messages from './messages';
 
@@ -61,9 +61,6 @@ const AddContentButton = ({ contentType, onCreateContent } : AddContentButtonPro
 
 const AddContentContainer = () => {
   const intl = useIntl();
-  const navigate = useNavigate();
-  const location = useLocation();
-  const currentPath = location.pathname;
   const { libraryId, collectionId } = useParams();
   const createBlockMutation = useCreateLibraryBlock();
   const updateComponentsMutation = useUpdateCollectionComponents(libraryId, collectionId);
@@ -73,6 +70,7 @@ const AddContentContainer = () => {
   const { showPasteXBlock } = useCopyToClipboard(canEdit);
   const {
     openCreateCollectionModal,
+    openComponentEditor,
   } = useLibraryContext();
 
   const collectionButtonData = {
@@ -151,14 +149,12 @@ const AddContentContainer = () => {
           blockType,
           definitionId: `${uuid4()}`,
         }).then((data) => {
-          const editUrl = getEditUrl(data.id);
+          const hasEditor = canEditComponent(data.id);
           updateComponentsMutation.mutateAsync([data.id]).catch(() => {
             showToast(intl.formatMessage(messages.errorAssociateComponentMessage));
           });
-          if (editUrl) {
-            // Pass currentPath in state so that we can come back to
-            // current page on save or cancel
-            navigate(editUrl, { state: { from: currentPath } });
+          if (hasEditor) {
+            openComponentEditor(data.id);
           } else {
             // We can't start editing this right away so just show a toast message:
             showToast(intl.formatMessage(messages.successCreateMessage));
diff --git a/src/library-authoring/collections/CollectionDetails.test.tsx b/src/library-authoring/collections/CollectionDetails.test.tsx
index 5c4e69064e..ad68c091d3 100644
--- a/src/library-authoring/collections/CollectionDetails.test.tsx
+++ b/src/library-authoring/collections/CollectionDetails.test.tsx
@@ -34,8 +34,6 @@ describe('<CollectionDetails />', () => {
   });
 
   afterEach(() => {
-    jest.clearAllMocks();
-    axiosMock.restore();
     fetchMock.mockReset();
   });
 
diff --git a/src/library-authoring/collections/LibraryCollectionPage.test.tsx b/src/library-authoring/collections/LibraryCollectionPage.test.tsx
index c1cfb9602f..b242601474 100644
--- a/src/library-authoring/collections/LibraryCollectionPage.test.tsx
+++ b/src/library-authoring/collections/LibraryCollectionPage.test.tsx
@@ -77,10 +77,6 @@ describe('<LibraryCollectionPage />', () => {
     });
   });
 
-  afterEach(() => {
-    jest.clearAllMocks();
-  });
-
   const renderLibraryCollectionPage = async (collectionId?: string, libraryId?: string) => {
     const libId = libraryId || mockContentLibrary.libraryId;
     const colId = collectionId || mockCollection.collectionId;
diff --git a/src/library-authoring/common/context.tsx b/src/library-authoring/common/context.tsx
index 772eaf17fb..5c4b1938db 100644
--- a/src/library-authoring/common/context.tsx
+++ b/src/library-authoring/common/context.tsx
@@ -25,6 +25,11 @@ export interface LibraryContextData {
   // Current collection
   openCollectionInfoSidebar: (collectionId: string) => void;
   currentCollectionId?: string;
+  // Editor modal - for editing some component
+  /** If the editor is open and the user is editing some component, this is its usageKey */
+  componentBeingEdited: string | undefined;
+  openComponentEditor: (usageKey: string) => void;
+  closeComponentEditor: () => void;
 }
 
 /**
@@ -45,6 +50,8 @@ export const LibraryProvider = (props: { children?: React.ReactNode, libraryId:
   const [currentComponentUsageKey, setCurrentComponentUsageKey] = React.useState<string>();
   const [currentCollectionId, setcurrentCollectionId] = React.useState<string>();
   const [isCreateCollectionModalOpen, openCreateCollectionModal, closeCreateCollectionModal] = useToggle(false);
+  const [componentBeingEdited, openComponentEditor] = React.useState<string | undefined>();
+  const closeComponentEditor = React.useCallback(() => openComponentEditor(undefined), []);
 
   const resetSidebar = React.useCallback(() => {
     setCurrentComponentUsageKey(undefined);
@@ -91,6 +98,9 @@ export const LibraryProvider = (props: { children?: React.ReactNode, libraryId:
     closeCreateCollectionModal,
     openCollectionInfoSidebar,
     currentCollectionId,
+    componentBeingEdited,
+    openComponentEditor,
+    closeComponentEditor,
   }), [
     props.libraryId,
     sidebarBodyComponent,
@@ -104,6 +114,9 @@ export const LibraryProvider = (props: { children?: React.ReactNode, libraryId:
     closeCreateCollectionModal,
     openCollectionInfoSidebar,
     currentCollectionId,
+    componentBeingEdited,
+    openComponentEditor,
+    closeComponentEditor,
   ]);
 
   return (
diff --git a/src/library-authoring/component-info/ComponentInfo.test.tsx b/src/library-authoring/component-info/ComponentInfo.test.tsx
new file mode 100644
index 0000000000..f200777bc3
--- /dev/null
+++ b/src/library-authoring/component-info/ComponentInfo.test.tsx
@@ -0,0 +1,63 @@
+import {
+  initializeMocks,
+  render,
+  screen,
+  waitFor,
+} from '../../testUtils';
+import { mockContentLibrary, mockLibraryBlockMetadata } from '../data/api.mocks';
+import { mockBroadcastChannel } from '../../generic/data/api.mock';
+import { LibraryProvider } from '../common/context';
+import ComponentInfo from './ComponentInfo';
+
+mockBroadcastChannel();
+mockContentLibrary.applyMock();
+mockLibraryBlockMetadata.applyMock();
+jest.mock('./ComponentPreview', () => ({
+  __esModule: true, // Required when mocking 'default' export
+  default: () => <div>Mocked preview</div>,
+}));
+jest.mock('./ComponentManagement', () => ({
+  __esModule: true, // Required when mocking 'default' export
+  default: () => <div>Mocked management tab</div>,
+}));
+
+const withLibraryId = (libraryId: string) => ({
+  extraWrapper: ({ children }: { children: React.ReactNode }) => (
+    <LibraryProvider libraryId={libraryId}>{children}</LibraryProvider>
+  ),
+});
+
+describe('<ComponentInfo> Sidebar', () => {
+  it('should show a disabled "Edit" button when the component type is not editable', async () => {
+    initializeMocks();
+    render(
+      <ComponentInfo usageKey={mockLibraryBlockMetadata.usageKeyThirdPartyXBlock} />,
+      withLibraryId(mockContentLibrary.libraryId),
+    );
+
+    const editButton = await screen.findByRole('button', { name: /Edit component/ });
+    expect(editButton).toBeDisabled();
+  });
+
+  it('should show a disabled "Edit" button when the library is read-only', async () => {
+    initializeMocks();
+    render(
+      <ComponentInfo usageKey={mockLibraryBlockMetadata.usageKeyPublished} />,
+      withLibraryId(mockContentLibrary.libraryIdReadOnly),
+    );
+
+    const editButton = await screen.findByRole('button', { name: /Edit component/ });
+    expect(editButton).toBeDisabled();
+  });
+
+  it('should show a working "Edit" button for a normal component', async () => {
+    initializeMocks();
+    render(
+      <ComponentInfo usageKey={mockLibraryBlockMetadata.usageKeyPublished} />,
+      withLibraryId(mockContentLibrary.libraryId),
+    );
+
+    const editButton = await screen.findByRole('button', { name: /Edit component/ });
+    await waitFor(() => expect(editButton).not.toBeDisabled());
+  });
+});
diff --git a/src/library-authoring/component-info/ComponentInfo.tsx b/src/library-authoring/component-info/ComponentInfo.tsx
index f503e4df99..19257b5de6 100644
--- a/src/library-authoring/component-info/ComponentInfo.tsx
+++ b/src/library-authoring/component-info/ComponentInfo.tsx
@@ -1,4 +1,3 @@
-import React from 'react';
 import { useIntl } from '@edx/frontend-platform/i18n';
 import {
   Button,
@@ -6,14 +5,15 @@ import {
   Tabs,
   Stack,
 } from '@openedx/paragon';
-import { Link } from 'react-router-dom';
 
-import { getEditUrl } from '../components/utils';
 import { ComponentMenu } from '../components';
 import ComponentDetails from './ComponentDetails';
 import ComponentManagement from './ComponentManagement';
 import ComponentPreview from './ComponentPreview';
 import messages from './messages';
+import { canEditComponent } from '../components/ComponentEditorModal';
+import { useLibraryContext } from '../common/context';
+import { useContentLibrary } from '../data/apiHooks';
 
 interface ComponentInfoProps {
   usageKey: string;
@@ -21,13 +21,15 @@ interface ComponentInfoProps {
 
 const ComponentInfo = ({ usageKey }: ComponentInfoProps) => {
   const intl = useIntl();
-  const editUrl = getEditUrl(usageKey);
+  const { libraryId, openComponentEditor } = useLibraryContext();
+  const { data: libraryData } = useContentLibrary(libraryId);
+  const canEdit = libraryData?.canEditLibrary && canEditComponent(usageKey);
 
   return (
     <Stack>
       <div className="d-flex flex-wrap">
         <Button
-          {...(editUrl ? { as: Link, to: editUrl } : { disabled: true, to: '#' })}
+          {...(canEdit ? { onClick: () => openComponentEditor(usageKey) } : { disabled: true })}
           variant="outline-primary"
           className="m-1 text-nowrap flex-grow-1"
         >
diff --git a/src/library-authoring/components/CollectionCard.test.tsx b/src/library-authoring/components/CollectionCard.test.tsx
index b2c7242f22..d95c542ffa 100644
--- a/src/library-authoring/components/CollectionCard.test.tsx
+++ b/src/library-authoring/components/CollectionCard.test.tsx
@@ -39,10 +39,6 @@ describe('<CollectionCard />', () => {
     initializeMocks();
   });
 
-  afterEach(() => {
-    jest.clearAllMocks();
-  });
-
   it('should render the card with title and description', () => {
     render(<CollectionCard collectionHit={CollectionHitSample} />);
 
diff --git a/src/library-authoring/components/ComponentCard.tsx b/src/library-authoring/components/ComponentCard.tsx
index 6e16937e8e..095512d2d8 100644
--- a/src/library-authoring/components/ComponentCard.tsx
+++ b/src/library-authoring/components/ComponentCard.tsx
@@ -7,7 +7,6 @@ import {
   Dropdown,
 } from '@openedx/paragon';
 import { MoreVert } from '@openedx/paragon/icons';
-import { Link } from 'react-router-dom';
 
 import { updateClipboard } from '../../generic/data/api';
 import { ToastContext } from '../../generic/toast-context';
@@ -15,8 +14,8 @@ import { type ContentHit } from '../../search-manager';
 import { useLibraryContext } from '../common/context';
 import messages from './messages';
 import { STUDIO_CLIPBOARD_CHANNEL } from '../../constants';
-import { getEditUrl } from './utils';
 import BaseComponentCard from './BaseComponentCard';
+import { canEditComponent } from './ComponentEditorModal';
 
 type ComponentCardProps = {
   contentHit: ContentHit,
@@ -24,7 +23,8 @@ type ComponentCardProps = {
 
 export const ComponentMenu = ({ usageKey }: { usageKey: string }) => {
   const intl = useIntl();
-  const editUrl = usageKey && getEditUrl(usageKey);
+  const { openComponentEditor } = useLibraryContext();
+  const canEdit = usageKey && canEditComponent(usageKey);
   const { showToast } = useContext(ToastContext);
   const [clipboardBroadcastChannel] = useState(() => new BroadcastChannel(STUDIO_CLIPBOARD_CHANNEL));
   const updateClipboardClick = () => {
@@ -48,7 +48,7 @@ export const ComponentMenu = ({ usageKey }: { usageKey: string }) => {
         data-testid="component-card-menu-toggle"
       />
       <Dropdown.Menu>
-        <Dropdown.Item {...(editUrl ? { as: Link, to: editUrl } : { disabled: true, to: '#' })}>
+        <Dropdown.Item {...(canEdit ? { onClick: () => openComponentEditor(usageKey) } : { disabled: true })}>
           <FormattedMessage {...messages.menuEdit} />
         </Dropdown.Item>
         <Dropdown.Item onClick={updateClipboardClick}>
diff --git a/src/library-authoring/components/ComponentEditorModal.tsx b/src/library-authoring/components/ComponentEditorModal.tsx
new file mode 100644
index 0000000000..a2b6cc3fe3
--- /dev/null
+++ b/src/library-authoring/components/ComponentEditorModal.tsx
@@ -0,0 +1,42 @@
+import { getConfig } from '@edx/frontend-platform';
+import React from 'react';
+
+import { useLibraryContext } from '../common/context';
+import { getBlockType } from '../../generic/key-utils';
+import EditorPage from '../../editors/EditorPage';
+
+/* eslint-disable import/prefer-default-export */
+export function canEditComponent(usageKey: string): boolean {
+  let blockType: string;
+  try {
+    blockType = getBlockType(usageKey);
+  } catch {
+    return false;
+  }
+
+  // Which XBlock/component types are supported by the 'editors' built in to this repo?
+  const mfeEditorTypes = ['html', 'problem', 'video'];
+  return mfeEditorTypes.includes(blockType);
+}
+
+export const ComponentEditorModal: React.FC<Record<never, never>> = () => {
+  const { componentBeingEdited, closeComponentEditor, libraryId } = useLibraryContext();
+
+  if (componentBeingEdited === undefined) {
+    return null;
+  }
+  const blockType = getBlockType(componentBeingEdited);
+
+  return (
+    <EditorPage
+      courseId={libraryId}
+      blockType={blockType}
+      blockId={componentBeingEdited}
+      studioEndpointUrl={getConfig().STUDIO_BASE_URL}
+      lmsEndpointUrl={getConfig().LMS_BASE_URL}
+      onClose={closeComponentEditor}
+      returnFunction={() => { closeComponentEditor(); return () => {}; }}
+      fullScreen={false}
+    />
+  );
+};
diff --git a/src/library-authoring/components/LibraryComponents.test.tsx b/src/library-authoring/components/LibraryComponents.test.tsx
index ac1a58a676..0e85cd7fe4 100644
--- a/src/library-authoring/components/LibraryComponents.test.tsx
+++ b/src/library-authoring/components/LibraryComponents.test.tsx
@@ -76,7 +76,6 @@ describe('<LibraryComponents />', () => {
 
   afterEach(() => {
     fetchMock.reset();
-    mockFetchNextPage.mockReset();
   });
 
   it('should render empty state', async () => {
diff --git a/src/library-authoring/components/utils.test.ts b/src/library-authoring/components/utils.test.ts
deleted file mode 100644
index 07d1265c5c..0000000000
--- a/src/library-authoring/components/utils.test.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-import { getEditUrl } from './utils';
-
-describe('component utils', () => {
-  describe('getEditUrl', () => {
-    it('returns the right URL for an HTML (Text) block', () => {
-      const usageKey = 'lb:org:ALPHA:html:571fe018-f3ce-45c9-8f53-5dafcb422fdd';
-      expect(getEditUrl(usageKey)).toStrictEqual(`/library/lib:org:ALPHA/editor/html/${usageKey}`);
-    });
-    it('returns the right URL for editing a Problem block', () => {
-      const usageKey = 'lb:org:beta:problem:571fe018-f3ce-45c9-8f53-5dafcb422fdd';
-      expect(getEditUrl(usageKey)).toStrictEqual(`/library/lib:org:beta/editor/problem/${usageKey}`);
-    });
-    it('returns the right URL for editing a Video block', () => {
-      const usageKey = 'lb:org:beta:video:571fe018-f3ce-45c9-8f53-5dafcb422fdd';
-      expect(getEditUrl(usageKey)).toStrictEqual(`/library/lib:org:beta/editor/video/${usageKey}`);
-    });
-    it('doesn\'t yet allow editing a drag-and-drop-v2 block', () => {
-      const usageKey = 'lb:org:beta:drag-and-drop-v2:571fe018-f3ce-45c9-8f53-5dafcb422fdd';
-      expect(getEditUrl(usageKey)).toBeUndefined();
-    });
-    it('returns undefined for an invalid key', () => {
-      expect(getEditUrl('foobar')).toBeUndefined();
-      expect(getEditUrl('')).toBeUndefined();
-      expect(getEditUrl('lb:unknown:unknown:unknown')).toBeUndefined();
-    });
-  });
-});
diff --git a/src/library-authoring/components/utils.ts b/src/library-authoring/components/utils.ts
deleted file mode 100644
index addaab73dc..0000000000
--- a/src/library-authoring/components/utils.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-import { getBlockType, getLibraryId } from '../../generic/key-utils';
-
-/* eslint-disable import/prefer-default-export */
-export function getEditUrl(usageKey: string): string | undefined {
-  let blockType: string;
-  let libraryId: string;
-  try {
-    blockType = getBlockType(usageKey);
-    libraryId = getLibraryId(usageKey);
-  } catch {
-    return undefined;
-  }
-
-  // Which XBlock/component types are supported by the 'editors' built in to this repo?
-  const mfeEditorTypes = ['html', 'problem', 'video'];
-  if (mfeEditorTypes.includes(blockType)) {
-    return `/library/${libraryId}/editor/${blockType}/${usageKey}`;
-  }
-  return undefined;
-}
diff --git a/src/library-authoring/data/api.mocks.ts b/src/library-authoring/data/api.mocks.ts
index c4ae602846..34b0279508 100644
--- a/src/library-authoring/data/api.mocks.ts
+++ b/src/library-authoring/data/api.mocks.ts
@@ -142,6 +142,7 @@ export async function mockXBlockFields(usageKey: string): Promise<api.XBlockFiel
     case thisMock.usageKeyNewHtml: return thisMock.dataNewHtml;
     case thisMock.usageKeyNewProblem: return thisMock.dataNewProblem;
     case thisMock.usageKeyNewVideo: return thisMock.dataNewVideo;
+    case thisMock.usageKeyThirdParty: return thisMock.dataThirdParty;
     default: throw new Error(`No mock has been set up for usageKey "${usageKey}"`);
   }
 }
@@ -172,6 +173,12 @@ mockXBlockFields.dataNewVideo = {
   data: '',
   metadata: { displayName: 'New Video' },
 } satisfies api.XBlockFields;
+mockXBlockFields.usageKeyThirdParty = 'lb:Axim:TEST:third_party:12345';
+mockXBlockFields.dataThirdParty = {
+  displayName: 'Third party XBlock',
+  data: '',
+  metadata: { displayName: 'Third party XBlock' },
+} satisfies api.XBlockFields;
 /** Apply this mock. Returns a spy object that can tell you if it's been called. */
 mockXBlockFields.applyMock = () => jest.spyOn(api, 'getXBlockFields').mockImplementation(mockXBlockFields);
 
@@ -192,6 +199,7 @@ export async function mockLibraryBlockMetadata(usageKey: string): Promise<api.Li
       throw createAxiosError({ code: 404, message: 'Not found.', path: api.getLibraryBlockMetadataUrl(usageKey) });
     case thisMock.usageKeyNeverPublished: return thisMock.dataNeverPublished;
     case thisMock.usageKeyPublished: return thisMock.dataPublished;
+    case thisMock.usageKeyThirdPartyXBlock: return thisMock.dataThirdPartyXBlock;
     case thisMock.usageKeyForTags: return thisMock.dataPublished;
     default: throw new Error(`No mock has been set up for usageKey "${usageKey}"`);
   }
@@ -228,6 +236,12 @@ mockLibraryBlockMetadata.dataPublished = {
   modified: '2024-06-21T13:54:21Z',
   tagsCount: 0,
 } satisfies api.LibraryBlockMetadata;
+mockLibraryBlockMetadata.usageKeyThirdPartyXBlock = mockXBlockFields.usageKeyThirdParty;
+mockLibraryBlockMetadata.dataThirdPartyXBlock = {
+  ...mockLibraryBlockMetadata.dataPublished,
+  id: mockLibraryBlockMetadata.usageKeyThirdPartyXBlock,
+  blockType: 'third_party',
+} satisfies api.LibraryBlockMetadata;
 mockLibraryBlockMetadata.usageKeyForTags = mockContentTaxonomyTagsData.largeTagsId;
 /** Apply this mock. Returns a spy object that can tell you if it's been called. */
 mockLibraryBlockMetadata.applyMock = () => jest.spyOn(api, 'getLibraryBlockMetadata').mockImplementation(mockLibraryBlockMetadata);
diff --git a/src/testUtils.tsx b/src/testUtils.tsx
index 73b2518f16..95c4b798c1 100644
--- a/src/testUtils.tsx
+++ b/src/testUtils.tsx
@@ -178,6 +178,9 @@ export function initializeMocks({ user = defaultUser, initialState = undefined }
     toastMessage: null,
   };
 
+  // Clear the call counts etc. of all mocks. This doesn't remove the mock's effects; just clears their history.
+  jest.clearAllMocks();
+
   return {
     reduxStore,
     axiosMock,