[BUG] PowerShell: Text rendering issues - invisible text and excessive input field height

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?

Two UI rendering issues when running Claude Code in PowerShell:

1. Invisible/partial text in Claude's responses

• Claude's response text is mostly invisible
• Only some characters appear intermittently
• Makes responses unreadable

1. Input field height bug

• The input field's background/highlight area is excessively tall
• Even short single-line messages show highlight spanning 2 lines
• 2-line messages show 4-line highlight, and so on
• The highlight area is always double the actual text height

What Should Happen?

1. All of Claude's response text should be fully visible and readable
2. Input field highlight/background should match the actual text height (1 line of text = 1 line of highlight)

Error Messages/Logs

No error messages. This is a visual/UI rendering issue.

Steps to Reproduce

1. Open PowerShell on Windows
2. Run claude to start Claude Code
3. Type any message and press Enter
4. Observe:

• Claude's response text is partially invisible (only some characters visible)
• The input field's highlight area is twice the height of actual text

1. Type a 2-line message
2. Observe: The highlight area spans 4 lines instead of 2

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.73

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

• Windows 11
• Claude Code version: 2.0.73
• The issue does NOT occur in Git Bash or VSCode integrated terminal
• Only occurs in PowerShell
• Tried both Windows PowerShell and PowerShell 7, same issue

<img width="1111" height="617" alt="Image" src="https://github.com/user-attachments/assets/5bc63702-1b23-40f3-b427-cee264caef66" />