fix(agent-manager): preserve side panels across context switches

[marius-kilocode]

What Problem This Solves

Switching from Local Diff to another worktree's Subagents could discard the selected panel. Edit previews could also disappear when returning to a session.

Why This Change Was Made

Store panel selection with its owner: Diff, PR, Terminal, and Documents belong to the worktree; Subagents, Edit Preview, and Browser belong to the session. Temporary hiding must not clear that selection.

The scope excludes PR-cache and Diff-scope routing changes. Regression coverage is limited to five focused cases rather than a broad matrix.

User Impact

Returning restores the selected panel and session preview. Explicitly closed panels stay closed. Setup events and Review/History visibility do not erase another context's panel. State is retained within the current Agent Manager webview, not across restarts.

Evidence

• Five added regression cases cover owner restoration, explicit closes, preview retention, ID-less setup completion, and a Terminal hidden by History/Review. The focused suite passes (130 tests, including existing coverage).
• Compile, lint, host/webview typechecks, formatting, and Knip pass.
• Repeated Local Diff/Subagents and mixed session/worktree switching in isolated VS Code: 18 assertions passed. Real UI controls used synthetic transport data; no live model, PTY, or setup script was exercised.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (2 files)

• packages/kilo-vscode/tests/unit/agent-manager-arch.test.ts
• packages/kilo-vscode/webview-ui/agent-manager/project/progress.ts

Previous Review Summaries (3 snapshots, latest commit 8fdc1bd)

Current summary above is authoritative. Previous snapshots are kept for context only.

Previous review (commit 8fdc1bd)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (14 files)

• packages/kilo-vscode/tests/unit/agent-manager-ambient-setup.test.ts
• packages/kilo-vscode/tests/unit/agent-manager-arch.test.ts
• packages/kilo-vscode/tests/unit/agent-manager-diff-scope-state.test.ts
• packages/kilo-vscode/tests/unit/agent-manager-terminal-side.test.ts
• packages/kilo-vscode/tests/unit/edit-preview.test.ts
• packages/kilo-vscode/tests/unit/pr-panel-state.test.ts
• packages/kilo-vscode/tests/unit/side-panel-state.test.ts
• packages/kilo-vscode/tests/unit/subagent-tabs.test.ts
• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx
• packages/kilo-vscode/webview-ui/agent-manager/diff-review-scope.ts
• packages/kilo-vscode/webview-ui/agent-manager/pr/PRComments.tsx
• packages/kilo-vscode/webview-ui/agent-manager/pr/PRPanel.tsx
• packages/kilo-vscode/webview-ui/agent-manager/pr/pr-comment-state.ts
• packages/kilo-vscode/webview-ui/agent-manager/subagent-tabs.ts

Previous review (commit b5ee423)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (7 files)

• packages/kilo-vscode/tests/unit/agent-manager-ambient-setup.test.ts
• packages/kilo-vscode/tests/unit/agent-manager-arch.test.ts
• packages/kilo-vscode/tests/unit/side-panel-state.test.ts
• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx
• packages/kilo-vscode/webview-ui/agent-manager/BrowserPanel.tsx
• packages/kilo-vscode/webview-ui/agent-manager/project/progress.ts
• packages/kilo-vscode/webview-ui/agent-manager/side-panel-state.ts

Previous review (commit cfc3d82)

Status: 2 Issues Found | Recommendation: Address before merge

Overview

Severity	Count
CRITICAL	0
WARNING	2
SUGGESTION	0

Issue Details (click to expand)

WARNING

File	Line	Issue
packages/kilo-vscode/webview-ui/agent-manager/project/progress.ts	40	ID-less ready/error does not clear an overlay that already has a worktreeId
packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx	549	Ambient setup sees the concealed panel, so History/Review looks like closed

Files Reviewed (20 files)

• .changeset/remember-subagent-panel.md
• packages/kilo-vscode/tests/unit/agent-manager-ambient-setup.test.ts
• packages/kilo-vscode/tests/unit/agent-manager-arch.test.ts
• packages/kilo-vscode/tests/unit/agent-manager-diff-scope-state.test.ts
• packages/kilo-vscode/tests/unit/agent-manager-terminal-side.test.ts
• packages/kilo-vscode/tests/unit/edit-preview.test.ts
• packages/kilo-vscode/tests/unit/pr-panel-state.test.ts
• packages/kilo-vscode/tests/unit/side-panel-state.test.ts
• packages/kilo-vscode/tests/unit/subagent-tabs.test.ts
• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx - 1 issue
• packages/kilo-vscode/webview-ui/agent-manager/diff-review-scope.ts
• packages/kilo-vscode/webview-ui/agent-manager/edit-preview.ts
• packages/kilo-vscode/webview-ui/agent-manager/pr/PRComments.tsx
• packages/kilo-vscode/webview-ui/agent-manager/pr/PRPanel.tsx
• packages/kilo-vscode/webview-ui/agent-manager/pr/pr-comment-state.ts
• packages/kilo-vscode/webview-ui/agent-manager/project/progress.ts - 1 issue
• packages/kilo-vscode/webview-ui/agent-manager/project/switch.ts
• packages/kilo-vscode/webview-ui/agent-manager/side-panel-state.ts
• packages/kilo-vscode/webview-ui/agent-manager/subagent-tabs.ts
• packages/kilo-vscode/webview-ui/agent-manager/terminal/ambient.ts

Fix these issues in Kilo Cloud

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_{Reviewed by grok-4.6 · Input: 103.9K · Output: 8.5K · Cached: 290.8K}

_{Review guidance: REVIEW.md from base branch main}