diff --git a/packages/core/src/extensions/code-block.test.ts b/packages/core/src/extensions/code-block.test.ts
index cd91414..a29a21e 100644
--- a/packages/core/src/extensions/code-block.test.ts
+++ b/packages/core/src/extensions/code-block.test.ts
@@ -1,6 +1,7 @@
+import { isFirefox } from '@meowdown/vitest/helpers'
 import { DOMParser, DOMSerializer } from '@prosekit/pm/model'
-import { describe, expect, it } from 'vitest'
-import { userEvent } from 'vitest/browser'
+import { describe, expect, it, vi } from 'vitest'
+import { page, userEvent } from 'vitest/browser'
 
 import { setupFixture } from '../testing/index.ts'
 
@@ -95,3 +96,38 @@ describe('dollar fence rules', () => {
     expect(fixture.doc.child(0).type.name).toBe('paragraph')
   })
 })
+
+const codeTokens = page.locate('.ProseMirror pre code [class*="tok-"]')
+
+describe('typing over code block selections', () => {
+  it('keeps the typed text over a partial selection', async () => {
+    using fixture = setupFixture()
+    const { n } = fixture
+    fixture.set(n.doc(n.codeBlock({ language: 'js' }, '<a>const answer = 4<b>2')))
+    // The bug only triggers once highlight token spans wrap the code text.
+    await expect.element(codeTokens.first(), { timeout: 15000 }).toBeInTheDocument()
+    fixture.view.focus()
+    await userEvent.keyboard('X')
+    const expected = n.doc(n.codeBlock({ language: 'js' }, 'X2'))
+    await vi.waitFor(() => {
+      expect(fixture.doc.eq(expected)).toBe(true)
+    })
+  })
+
+  it.skipIf(
+    // Firefox edits the text node in place and is not affected.
+    isFirefox(),
+  ).fails('keeps the typed text over the full code text', async () => {
+    using fixture = setupFixture()
+    const { n } = fixture
+    fixture.set(n.doc(n.codeBlock({ language: 'js' }, '<a>const answer = 42<b>')))
+    // The bug only triggers once highlight token spans wrap the code text.
+    await expect.element(codeTokens.first(), { timeout: 15000 }).toBeInTheDocument()
+    fixture.view.focus()
+    await userEvent.keyboard('X')
+    const expected = n.doc(n.codeBlock({ language: 'js' }, 'X'))
+    await vi.waitFor(() => {
+      expect(fixture.doc.eq(expected)).toBe(true)
+    })
+  })
+})
diff --git a/packages/react/src/components/code-block-view.test.tsx b/packages/react/src/components/code-block-view.test.tsx
index e1dcfef..aaa5132 100644
--- a/packages/react/src/components/code-block-view.test.tsx
+++ b/packages/react/src/components/code-block-view.test.tsx
@@ -1,6 +1,8 @@
 import '../testing/index.ts'
 
-import { isSafari } from '@meowdown/vitest/helpers'
+import { isFirefox, isSafari } from '@meowdown/vitest/helpers'
+import { TextSelection } from '@prosekit/pm/state'
+import type { EditorView } from '@prosekit/pm/view'
 import { createRef } from 'react'
 import { describe, expect, it, vi } from 'vitest'
 import { render } from 'vitest-browser-react'
@@ -160,3 +162,67 @@ describe('code block math preview', () => {
     })
   })
 })
+
+describe('typing over code block selections', () => {
+  async function setupHighlightedCodeBlock(onDocChange?: VoidFunction) {
+    const ref = createRef<EditorHandle>()
+    await render(
+      <ProseKitEditor ref={ref} initialMarkdown={CODE_BLOCK_MD} onDocChange={onDocChange} />,
+    )
+    // The bug only triggers once highlight token spans wrap the code text.
+    await expect.element(tokens.first(), { timeout: 15000 }).toBeInTheDocument()
+    const view = ref.current?.editor?.view
+    if (!view) throw new Error('editor not mounted')
+    const codeStart = 1
+    const codeEnd = codeStart + view.state.doc.child(0).content.size
+    return { ref, view, codeStart, codeEnd }
+  }
+
+  function selectCodeRange(view: EditorView, anchor: number, head: number) {
+    view.dispatch(view.state.tr.setSelection(TextSelection.create(view.state.doc, anchor, head)))
+    view.focus()
+  }
+
+  it('updates the markdown when typing at a caret', async () => {
+    const { ref, view, codeEnd } = await setupHighlightedCodeBlock()
+    selectCodeRange(view, codeEnd, codeEnd)
+    await userEvent.keyboard('X')
+    await vi.waitFor(() => {
+      expect(ref.current?.getMarkdown()).toContain('fn main() {}X')
+    })
+  })
+
+  it('updates the markdown when typing over a partial selection', async () => {
+    const { ref, view, codeStart, codeEnd } = await setupHighlightedCodeBlock()
+    selectCodeRange(view, codeStart, codeEnd - 1)
+    await userEvent.keyboard('X')
+    await vi.waitFor(() => {
+      expect(ref.current?.getMarkdown()).toContain('```rust\nX}\n```')
+    })
+  })
+
+  it.skipIf(
+    // Firefox edits the text node in place and is not affected.
+    isFirefox(),
+  ).fails('updates the markdown when typing over the full code text', async () => {
+    const { ref, view, codeStart, codeEnd } = await setupHighlightedCodeBlock()
+    selectCodeRange(view, codeStart, codeEnd)
+    await userEvent.keyboard('X')
+    await vi.waitFor(() => {
+      expect(ref.current?.getMarkdown()).toContain('```rust\nX\n```')
+    })
+  })
+
+  it.skipIf(
+    // Firefox edits the text node in place and is not affected.
+    isFirefox(),
+  ).fails('notifies onDocChange when typing over the full code text', async () => {
+    const onDocChange = vi.fn()
+    const { view, codeStart, codeEnd } = await setupHighlightedCodeBlock(onDocChange)
+    selectCodeRange(view, codeStart, codeEnd)
+    await userEvent.keyboard('X')
+    await vi.waitFor(() => {
+      expect(onDocChange).toHaveBeenCalled()
+    })
+  })
+})