fix(ios): iPad sidebar tabs no longer stick on the wrong tab

[PixPMusic]

Problem

On iPad, the Threads / Pull requests picker at the top of the sidebar drifts out of sync. After switching to Pull requests and back to Threads, the thread list shows but "Pull requests" stays highlighted. On the next trip the reverse happens: the list stays on pull requests, and tapping Threads does nothing, because SwiftUI thinks that segment is already selected. It alternates on every round trip, so it looks intermittent.

Cause

WorkspaceNativeTabs retains a separate copy of the workspace tree for each tab, and each copy has its own picker. Tapping a segment moves that SwiftUI picker immediately, then the tab switch freezes the tree it lives in. When that tab comes back, React renders the same selection the frozen copy last had, so nothing reaches the native picker and it keeps showing the segment tapped before. Instrumenting the flow showed the stuck tap never reaches onSelect.

Fix

Key the picker on selectionRevision, which the workspace state already bumps on every tab switch, and which the root header already uses to refresh the retained trees. Whichever copy becomes visible mounts a fresh picker from the current selection. The copy that was tapped is frozen and hidden at that point, so the remount isn't visible.

Why this qualifies as a small focused fix

It's one obvious defect: the sidebar picker shows the wrong tab and ignores taps. The fix is one key in one component and changes no behavior beyond keeping the picker in sync. It affects only the wide iPad layout, where this picker appears.

Verification

• iOS 26.5 iPad simulator, isolated server with synthetic showcase data.
  • On main, from a fresh launch, a single Pull requests → Threads round trip leaves Pull requests highlighted over the thread list. Opening a thread first and then switching tabs left the app stuck on Pull requests every other cycle.
  • With the fix, 8 of 8 cycles of open a thread → Pull requests → Threads ended on Threads, with delays between taps from 0.3s to 3s. Three plain Pull requests ↔ Threads round trips showed the matching list and highlight each time.
• vp lint and vp fmt --check on the changed file are clean, and vp run typecheck in apps/mobile passes.
• No unit test: the defect lives in the native picker's own state across React Native screen freezing, which isn't reachable from the existing JS tests.

Before / After

iPad, after one Pull requests → Threads round trip from a fresh launch.

Before	After

#20133 also touches this file (it moves the selection handler into a shared hook) and will need a one-line rebase after either one merges.

Model: Claude Opus 5.5 | Harness: Claude Code in T3 Code

[macroscopeapp]

Approvability

Verdict: Approved at d33882e

Macroscope's review found this PR approvable — This is a four-line, iOS-only fix that remounts the existing sidebar picker on workspace tab switches so its native selection cannot remain stale. The change is isolated to the iPad/sidebar UI and introduces no new capability, schema, default, or static-analysis override.

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[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between d33882e and 627cdb3.

📒 Files selected for processing: 1

• apps/mobile/src/features/workspace/WorkspaceSidebarTabs.ios.tsx

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📝 Walkthrough

The iOS workspace sidebar now uses workspace.state.selectionRevision as the SegmentedControl key. The control remounts when that value changes.

Changes: Workspace sidebar picker

Layer / File(s)	Summary
Segmented control remount apps/mobile/src/features/workspace/WorkspaceSidebarTabs.ios.tsx	The SegmentedControl key now uses workspace.state.selectionRevision. A comment describes the iOS picker behavior.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~3 minutes

Change: Bug fix

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 627cd

The picker remounts when the selected tab changes while continuing to receive the current selection. No concrete merge-blocking risk is established.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title clearly and concisely describes the iPad sidebar picker fix.
Description check		The description explains the problem, cause, fix, focused scope, verification results, limitations, and before/after evidence. It also explains why the change qualifies as a small focused fix without …
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Description check

Explanation

The description explains the problem, cause, fix, focused scope, verification results, limitations, and before/after evidence. It also explains why the change qualifies as a small focused fix without a linked issue.

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