Row under the composer has no background, so chat text shows through it when you scroll #27512

What happened

In a thread with messages, when "keep composer context visible" is on, the row under the composer (machine name, branch) has no background. When you scroll the conversation, the chat text shows behind and around the machine name and branch labels, and the two overlap.

Diagnosis

#25869 changed ComposerSurface.ContextStrip to "a plain row under the card … with no surface of its own". When the row is shown, Shell hides its glass ::before (data-context-row:before:hidden), and only Host (the card) paints glass. Nothing paints behind the row, but the timeline still scrolls under it.

Before #25869, the strip had its own fill. #25335 had fixed a related case where the strip lost its background under attached banners.

Steps to reproduce

1. Turn on "keep composer context visible".
2. Open a thread in a git project with enough messages to scroll.
3. Scroll the conversation so text passes behind the row under the composer.

Expected: The row has a background, like the composer, or the timeline ends above the row.

Actual: Chat text shows through the row and overlaps the machine name and branch labels.

Environment

• Version: T3 Code Desktop 0.1.4-nightly.20261028.3824
• OS: macOS 26 (arm64), dark mode
• The code is unchanged on main as of 0.1.6-nightly.20261030.3917.

Evidence

Related

#25869 (cause), #25335, #12937, #26635, #26958, PR #25773

Written with T3 triage, by Claude Opus 5.5 in Claude Code.