Window menu — naming options & edge cases

No subtitle — the welcome screen has no count to report, and navigationSubtitle already returns empty here. Two welcome windows stay identical, which is correct: they are identical.

Falls back to bare title, no parentheses — the existing behaviour when the session count is nil. Nothing to decide.

Subtitle localises, project name does not — it is the researcher's own data. Already true today; adding the lens name adds one more translated token per locale, which the existing lensSubtitle helpers already own.

Corrected 18 Aug 2026 — the recommendation below was reasoned from a premise that was only ever temporary, and the code shipped the other way. The ordinal stays.

The argument turned on "these are two views of one project, not two projects". That described Stage 3a — one serve, one study at a time — and not the product. The end goal is explicitly both: docs/design-workspace.md §"Stage 3b" is "two projects visible at once ⇒ two sidecars", and the memory objection that was holding it open was measured and retired on 16 Aug (~140 MB per additional project, flat from 1 to 8 windows).

Under the real model the ordinal fires far more narrowly than this card assumed — two different studies are told apart by name, two lenses by subtitle, so the suffix only ever appears when two rows are genuinely byte-identical. That is precisely the case Mail, Finder and Safari leave you stuck in, and "numbering implies the second is a copy" is weakest exactly where the ordinal actually fires — because in that case the two rows really are indistinguishable.

Two things settled since, both worth not re-deriving. Measured: AppKit's automatic Window-menu path renders Title (Subtitle); the manual addWindowsItem path renders title only. So keying the duplicate group on the rendered subtitle is correct by construction, not by luck. And master/child makes this common rather than exotic: a child is a second window on the same study, so two children at one lens is the ordinary shape of the feature, not an edge.

Superseded text, kept because the reasoning is worth seeing:

Mail, Finder and Safari all permit duplicate rows and do nothing about it. The ordinal suffix is the document convention (Untitled 2) and it is wrong here — these are two views of one project, not two projects, and numbering implies the second is a copy.

Recommendation: accept the duplicate. If the two windows genuinely diverge — different filter, different scroll — the subtitle already diverges with them, because it is computed from live filter state.

This is the only case where the client folder earns its place — and note it earns it in the subtitle, not as a title prefix.

Conditional inclusion is tempting and I would not do it: a subtitle that changes shape depending on what other windows are open is unpredictable, and the researcher cannot learn the rule. Either always or never. Given the counts already differ in the failing case, never is defensible and cheaper — revisit only if a real cohort project hits it.

Zero happens routinely — an over-narrow filter, a tag with nothing under it. Reporting 0 shown in a window title is noise about a state the researcher can already see on screen. Dropping to the bare lens name keeps the window identifiable and stops the title commenting on the filter. Prefer the second.

Mail does put live state in the title (the unread count moves). But Bristlenose already decided where run status lives: on the project's sidebar row, because status lives where its subject lives. A title that narrates the run duplicates that in a place the researcher is not looking, and it churns the Window menu once a second.

Recommendation: leave it out. The exception worth considering is a window whose project is running while the sidebar is hidden — but that argues for the toolbar, not the title.

The menu grows to fit; there is no wrapping. Mail's own entry in the reference above is 67 characters, so a wide Window menu is within precedent rather than a defect — and the folder name from E5 would push it further.

The researcher named the project, so truncating their words to preserve our count is the wrong trade. If anything is dropped at width, drop the subtitle.

Three things resolved by drawing it whole:

• The stray Bristlenose command above the tab items goes away. Today it is openWindow(id: "main") against a WindowGroup, which spawns a window rather than reopening one — it is a New Window command wearing a reopen label, and it belongs in File as New Viewer Window with the ⇧⌘O that is currently dead.
• The player pop-out becomes Ben — IKEA Study (Video): participant, study, kind. Its current s3 — Bristlenose shows a speaker code no one outside the pipeline reads, and appends the app name in a list where every row is this app.
• Auxiliary windows (System Health, and the Diagnostics tools) sit here already and need nothing — they are single-instance and their names are unambiguous.