Markdown preview fails to load

Support Bug Reports
1

Describe the Bug

I found a specific markdown content that breaks the built-in “Preview” tab of a markdown editor. It started after a plan failed to render, and I reduced to a minimum reproducible content, shown below. The same contents render just fine in the standard vscode “Markdown: open preview” feature. See steps to reproduce and the attached screenshots and video recording.

Markdown contents:

1. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin in augue ut eros sodales tincidunt sed at sapien. Integer leo mi, sagittis eu sollicitudin eleifend, cursus vitae nisi. Duis finibus pretium urna, eget pulvinar arcu aliquet ac. Curabitur integer.

2. Vestibulum blandit suscipit risus, quis lacinia felis hendrerit vel. Nunc scelerisque id ante vel venenatis. Aliquam vitae consectetur erat. Maecenas vel orci eros. Pellentesque efficitur nisi eget nunc finibus, sed accumsan.

3. Donec elit quam, vestibulum id mi eget, dignissim pulvinar nisi. Pellentesque vehicula lacus sit amet.

### Test 1
- Test 2
  > Test 4

  Test 5

Error:

workbench.desktop.main.js:6323 Uncaught RangeError: Invalid content for node listItem: <paragraph("Test 2"), blockquote(paragraph("Test 4
    at NodeType.checkContent (workbench.desktop.main.js:6323:2428)
    at Node.check (workbench.desktop.main.js:6322:145193)
    at workbench.desktop.main.js:6322:145536
    at Fragment.forEach (workbench.desktop.main.js:6322:133926)
    at Node.check (workbench.desktop.main.js:6322:145523)
    at workbench.desktop.main.js:6327:55074
    at Fragment.forEach (workbench.desktop.main.js:6322:133926)
    at workbench.desktop.main.js:6327:55060
    at Object.method [as insertContentAt] (workbench.desktop.main.js:6327:47195)
    at workbench.desktop.main.js:712:168

Steps to Reproduce

  1. Create a markdown file with the contents below
  2. Click on the “Preview” tab
  3. Confirm nothing renders

Screenshots / Screen Recordings

Operating System

Windows 10/11

Version Information

Version: 3.9.0 (user setup)
VS Code Extension API: 1.105.1
Commit: f2f5f794810366931ac8203e783b3dfeb3c78a50
Date: 2026-06-22T22:59:34.874Z
Layout: editor
Build Type: Stable
Release Track: Nightly
Electron: 40.10.3
Chromium: 144.0.7559.236
Node.js: 24.15.0
V8: 14.4.258.32-electron.0
xterm.js: 6.1.0-beta.256
OS: Windows_NT x64 10.0.26200

Does this stop you from using Cursor

No - Cursor works, but with this issue

8

Hi @terracota Thank you very much for the detailed bug report and the video! I was able to reproduce this on 3.9 as well.

I’ve filed a bug report for this and we’ll keep you updated on the status of it. It looks like this was introduced in 3.9, since I’m not seeing the same behavior on prior versions such as 3.8.

For now, the standard Markdown: Open Preview command appears to render this content correctly as you mentioned, so that may be a useful workaround while we track the built-in Preview tab issue.