[nplez1]

	Files	Added	Deleted	Net
Test	1	$\color{#1a7f37}{\Huge{\mathbf{+}}}$​114	0	$\color{#1a7f37}{\Huge{\mathbf{+}}}$​114
Prod	2	$\color{#1a7f37}{\Huge{\mathbf{+}}}$​67	$\color{#cf222e}{\Huge{\mathbf{−}}}$​7	$\color{#1a7f37}{\Huge{\mathbf{+}}}$​60

ELI5

When the same branch is checked out on two machines, the sidebar shows them as one card with a small dropdown to pick the machine. Picking a different machine changed what the card showed, but the app stayed "on" the old machine, so nothing in the list looked selected anymore. Now picking a machine also switches the app to that machine's copy.

What Changed

Before: with Workspaces grouped by Project and "Group by branch" on, selecting a consolidated card and then changing the host dropdown swapped the card to the new host's workspace, but the card appeared unselected. The previously active workspace — whose row is merged into that same card — had no visible selection anywhere in the list.

After: changing the dropdown makes the chosen host's workspace the active workspace, so the card stays selected and its status, branch, PR, tabs and agents follow it.

Mechanism: the dropdown only wrote the ephemeral branchGroupHostByKey slice field that decides which member a consolidated card renders. The host-switch path now also runs the same activation a card click uses (activateWorktreeFromSidebar(worktree.id, hostId)) plus the click-path immediate marking. The member is resolved by branch group key + host from the row's branchGroup, not by row.worktree, because a merged row always stores its local-first member while the card can be displaying any host.

Why

The alternative was to make the store's setBranchGroupHost setter activate the workspace itself. That setter is a pure state mutation shared with the tab strip, so putting activation side effects inside it is a layering problem and would also fire while state is being rehydrated. Activating on the interaction path keeps the setter pure and reuses the existing activation flow.

Linked Issue

Issues are disabled in this fork, so there is no issue to link. Follow-up to the Group by branch host dropdown introduced in #14.

Related: #14

Visual Proof

N/A — reproducing needs two workspaces on the same branch on two different hosts, and the change alters selection/activation behavior rather than adding or moving any visual element. Covered by the new unit tests.

Testing

• pnpm test src/renderer/src/components/sidebar/worktree-list/viewport/use-branch-group-host-selection.test.ts — 4 passed (non-primary member resolves and activates with the correct hostId; host choice still recorded when the row is gone).

• pnpm test src/renderer/src/components/sidebar — 315 files / 2661 tests passed.

• pnpm tc, oxfmt --check, and pnpm run check:code-quality:changed are clean.

• Platforms: renderer logic only, no platform-specific code. Host switching passes the member's execution host id through the same path as a card click, so remote/SSH hosts are covered by construction.

• I manually tested these changes locally

• Automated tests added/updated, or explained why not below

AI Disclosure

N/A — internal contributor.

Review

Agent skill upstream boundary

• Not applicable, or this change follows docs/reference/agent-skill-sharing-upstream-boundary.md and copies or mechanically translates no upstream skill-installer source, tests, fixtures, registry entries, path tables, comments, or documentation.

Notes

Security: no new inputs or data flows; the handler is a lookup over already-rendered rows. Performance: O(rows) only on dropdown click, and the returned handler stays referentially stable so memoized cards do not re-render. Cross-platform / SSH: activation goes through activateWorktreeFromSidebar with the member's hostId, matching the card-click path used for remote hosts.

Checklist

• This PR is small and focused
• I explained what changed and why (ELI5, the user-facing before/after, the mechanism, and why over the alternatives)
• Before/after screenshots or videos attached for UI changes, or N/A with reason
• Self-reviewed for correctness, security, and performance
• Cross-platform, SSH/remote, and path/shortcut impact considered (or N/A)
• pnpm lint, pnpm typecheck, pnpm test, and pnpm build pass (or CI will cover; local preferred)