input lag when typing - 5+ second delay

[0b11111110]

What happened?

Bug Report: Severe Input Lag in Chat Window

Extension Information

• Extension ID: qwenlm.qwen-code-vscode-ide-companion
• Extension Name: Qwen Code Companion
• Version: v0.12.3
• VS Code Version: 1.111.0
• OS: Windows 11
• Python: 3.12

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Issue Summary

Title: Severe input lag when typing - 5+ second delay

Severity: 🔴 Critical - Makes extension unusable

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Description

When typing in the Qwen Code Companion chat window, there is extreme input lag (5+ seconds delay) between pressing keys and text appearing on screen.

The lag is so severe that:

• I have to mentally track what I've already typed vs what hasn't appeared yet
• Long messages become extremely difficult to compose
• The extension becomes practically unusable for conversation

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Reproduction Steps

1. Open VS Code
2. Open Qwen Code Companion chat panel
3. Start typing a message (especially noticeable with messages >50 characters)
4. Observe 5+ second delay between typing and text appearing

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Actual Behavior

• Text appears with 5+ second delay after typing
• Have to mentally track what I've typed vs what's displayed
• Lag worsens with longer messages
• Makes conversation extremely difficult and frustrating

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Additional Context

• ✅ Chat functionality works correctly otherwise
• ✅ AI responses display correctly
• ❌ Only INPUT is laggy, not output
• Project context: Large Python project with extensive conversation history
• Lag may be related to:
  • Real-time context synchronization with file system?
  • Large conversation history being processed on every keystroke?
  • Syntax highlighting in input field?
  • Auto-complete suggestions processing?
  • Memory leak in input handler?

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System Resources During Lag

• CPU Usage: < 30%
• Memory Usage: 86%
• VS Code Memory in Taskmgr.exe: 3 900 MB

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Workarounds

1. Typing in external editor (Notepad) and pasting works fine
2. Other functions in VS Code work fine
3. Restarting VS Code temporarily NOT helps

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Logs & Diagnostics

Console Has No Errors

Extension Logs

VS Code → Output → "Qwen Code Companion"
empty

Project Size

# PowerShell (Windows):
dir /s /b *.py | find /c /v ""
# My project: 3429 Python files  (including .venv)

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Impact

This bug makes the extension practically unusable for:

• Extended conversations
• Code review discussions
• Debugging sessions
• Any workflow requiring typed input

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Priority

🔴 Critical - Core functionality broken

What did you expect to happen?

Expected Behavior

• Text should appear immediately as I type (<100ms delay)
• Responsive, smooth input experience
• No noticeable lag regardless of message length

Client information

Qwen Code: 0.12.3 (f1ee463)
Среда выполнения: Node.js v22.22.0 / npm unknown
ОС: win32 x64 (10.0.26200)
Аутентификация: Qwen OAuth
Модель: coder-model
ID сессии: 72af2476-5360-480f-869b-6577b7848dd8
Песочница: no sandbox
Прокси: no proxy
Использование памяти: 279.4 MB

Login information

No response

Anything else we need to know?

No response

[yiliang114]

Thanks for the report. From the screenshot, it looks like this may already be a fairly long conversation, so I wanted to confirm whether the input lag mainly happens when the chat history gets long. Do you also see the same noticeable lag in a brand-new session?

I’ll try to reproduce this as soon as possible and investigate it quickly, since this looks quite disruptive to the typing experience.

[0b11111110]

Do you also see the same noticeable lag in a brand-new session?

no, absolutely not, I haven't these problems in short sessions. but why there are lags in user's textbox in general?

[0b11111110]

oh! and if I just paste my text into text box - textbox just shows it in a moment, so I need temp document to writing promts in it, then copy-paste

[yiliang114]

@0b11111110 Thanks for the extra details.

It does sound like this may be related to longer conversations. Could you help confirm one more detail: did the lag only start after you had continued the conversation for many turns directly in VS Code IDE Companion, or did it appear after you selected or resumed an already long session that was originally created in the CLI?

Either way, I'll try to reproduce this as soon as possible and work on addressing it.

[0b11111110]

@0b11111110 Thanks for the extra details.

It does sound like this may be related to longer conversations. Could you help confirm one more detail: did the lag only start after you had continued the conversation for many turns directly in VS Code IDE Companion, or did it appear after you selected or resumed an already long session that was originally created in the CLI?

Either way, I'll try to reproduce this as soon as possible and work on addressing it.

directly in VS Code. on this computer i can't use cli. i haven't node.js