Chinese IME stutters while typing in the chat composer (Windows)

Support Bug Reports
, ,
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

On Windows, typing with a Chinese IME in the chat / agent composer intermittently stutters. Composition (preedit) updates fall behind keystrokes. The characters do eventually appear, and sending the message still works. The code editor does not show the same lag. It can happen on a fresh chat, and it is more noticeable while an agent reply is streaming or when a conversation is long.

Steps to Reproduce

  1. On Windows, enable a Chinese IME (for example Microsoft Pinyin).
  2. Open the chat / agent composer.
  3. Switch to Chinese input and type a sentence in pinyin.
  4. The composition text lags behind the keystrokes. This shows up more often while a reply is streaming, or after the conversation has grown long.

Expected Behavior

IME composition in the chat composer should update as smoothly as typing in the code editor, without visible stalls between keystrokes.

Operating System

Windows 10/11

Version Information

IDE:
Version: 3.24.12
VSCode Version: 1.128.0
Commit: 37b865941ccb31e2fc90c685157534efca87f960
OS: Windows_NT x64 10.0.22621

For AI issues: which model did you use?

Not model-specific. The lag happens while typing, before a request is sent.

For AI issues: add Request ID with privacy disabled

N/A. The lag happens during IME composition, before a request is sent.

Additional Information

This report is specifically Chinese IME composition lag in the chat composer on Windows. Latin input in the same box, and typing in the code editor, feel fine.

Related reports, but not the same bug:

  • Linux: the first Chinese or Korean character cannot be typed into an empty field (fcitx5 / ibus). See the topic “Unable to input Chinese characters directly in Cursor input fields”.
  • Glass layout general input lag: Laggy typing in agents window
  • Chat slowdown after many agent chats, which is worse with a CJK IME: Chat slowdown after many agent chats?

Workarounds that reduce it: Developer: Reload Window; switch Agents from the Glass layout to the classic layout; delete old chats.

Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

5

Hey @l1bing, thanks for the report, and for already narrowing it down to the Agents window and listing what helps.

Could you run through these steps so we can pin down when it happens?

  1. Open the Agents window
  2. Start a new chat and send a prompt that produces a long answer, for example “Explain this project in detail”.
  3. While the answer is still streaming, click into the chat box, switch to Microsoft Pinyin, and type a full sentence.
  4. Wait for the answer to finish, then type the same sentence again.
  5. Switch to the classic layout and repeat steps 2 to 4.

Does the composition lag in step 3 only, or in step 4 too? And does the classic layout lag at all?

If you can, please also capture a short recording while it lags: Help > Toggle Developer Tools > Performance tab, click Record, type in Pinyin for about 10 seconds, click Stop, then right-click the timeline, choose “Save profile”, and attach the file here.

In the meantime, the classic layout, a Reload Window, and deleting old chats are the best ways to reduce it, as you found.