[BUG] VS Code extension: "Show more" on a collapsed user message renders as a narrow column with per-letter wrapping, overlapping the text

What happened

In the Claude Code VS Code extension chat, after collapsing a long user message with "Show less", the "Show more" control is rendered broken:

• The button is only visible on hover over the collapsed message.
• It is squeezed into a narrow column (~40px wide): the label wraps letter-by-letter (Sho / w / mor / e).
• It is positioned over the faded text in the top-left corner of the message block, instead of below it.

Clicking the broken button does expand the message again, and "Show less" then renders normally. So only the collapsed-state "Show more" is affected.

!Show less normal → collapsed → Show more broken

Left: expanded message with normal "Show less". Middle: collapsed message (no control visible). Right: hovering the collapsed message shows the squeezed "Show more".

Steps to reproduce

1. Send a user message long enough to be truncated (here: a message with a fenced code block in Cyrillic, ~15 lines).
2. Expand it with "Show more", then click Show less.
3. Hover the collapsed message.

Expected

"Show more" renders as a normal full-width button below the collapsed text, like "Show less" does.

Actual

"Show more" is a narrow vertical column with per-letter wrapping, overlapping the message text, visible only on hover.

Environment

• Claude Code VS Code extension: anthropic.claude-code v2.1.270 (darwin-arm64)
• VS Code: 1.137.0 (commit 645f29cc3176500b4b5762ba887cf2a7f0ffdf2c, 2026-09-08)
• Electron: 42.10.0 · Chromium: 148.0.7778.280 · Node.js: 24.18.1
• OS: macOS (Darwin arm64 27.0.0)
• Not specific to these versions: the same behavior was reproducing on earlier versions of the extension / VS Code / macOS as well.

Related but different: #77004 (Show less off-screen), #85792 / #80672 (no collapse control at all).

🤖 Generated with Claude Code