[BUG] Claude Desktop (Windows x64 1.1.2685) — Shift+Enter sends message instead of inserting newline in Code tab

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

In Claude Desktop for Windows, pressing Shift+Enter in the Code tab input field sends the message immediately instead of inserting a newline. The same keyboard shortcut works correctly in the Chat tab, where it inserts a newline as expected.

• Chat tab: Shift+Enter correctly inserts a newline ✅
• Code tab: Shift+Enter submits the message (same as Enter) ❌

This makes it impossible to compose multi-line prompts in the Code tab. Since the Code tab is specifically designed for coding tasks where multi-line input (code snippets, structured prompts) is common, this significantly impacts usability.

What Should Happen?

Shift+Enter should insert a newline in both the Chat tab and the Code tab input fields, consistent with the industry-standard behavior used in virtually all modern messaging and code editing interfaces (Slack, Discord, VS Code, ChatGPT, etc.).

The bug likely originates in the frontend input handler for the Code tab, which does not check for event.shiftKey before triggering message submission on Enter.

Error Messages/Logs

Steps to Reproduce

1. Open Claude Desktop
2. Switch to the Chat tab
3. Type some text in the input field
4. Press Shift+Enter → ✅ A newline is inserted (correct behavior)
5. Switch to the Code tab
6. Type some text in the input field
7. Press Shift+Enter → ❌ The message is sent instead of inserting a newline

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.39

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_