Two cases in `agent-modals-mobile` asserted DOM shapes that the FN-8619
`FloatingWindow` migration deliberately retired. Both are **stale
expectations, not product regressions** — established below rather than
assumed, because "delete the failing assertion" is exactly how a real
bug gets buried.
### 1. `AgentDetailView` — the suite asserted both sides of the same
fact
```js
expect(document.querySelector(".agent-detail-overlay")).toBeTruthy(); // here — RED
```
```js
expect(document.querySelector(".agent-detail-overlay")).toBeNull(); // AgentDetailView.core.test.tsx:97 — GREEN
```
No component renders that class (`grep` across `app/**/*.tsx` outside
tests: zero hits). One of these two had to be red, and the one matching
the product is the `toBeNull` sibling. This case now asserts the panel
class it is actually named for — `.agent-detail-modal`, which **is**
live and **is** what the mobile `@media` block in `AgentDetailView.css`
targets — and pins the scrim as still-retired.
I did **not** re-point the overlay half at `.floating-window-overlay`.
That would only re-assert FloatingWindow's own contract (already covered
by `FloatingWindow.test.tsx`) while saying nothing about Agent Detail
being mobile-targetable.
### 2. `AgentGenerationModal` — the class belongs to a different
component
It demanded `.agent-dialog-overlay`. That class is **still live** —
`NewAgentDialog.tsx:415` renders it — which is why the stale expectation
looked plausible and survived. But this modal is a `FloatingWindow` with
`modal` (`AgentGenerationModal.tsx:162`), so its scrim is
`.floating-window-overlay--modal`. Now asserted explicitly, because "a
modal blocks the app beneath it" is a real FN-8619 contract worth
pinning.
### Why the dead CSS is still here
`.agent-detail-overlay` has 4 CSS definitions and one inert mobile
`@media` rule. I deliberately did **not** delete them in this PR:
- Two **passing** tests (`dashboard-overflow-containment.test.tsx:295`,
`mobile-horizontal-pan-containment.test.ts:90`) pin a selector *string*
that lists `.agent-detail-overlay`. Deleting the CSS turns two green
tests red.
- That raises a question I cannot answer without rendering, and I will
not boot an instance to find out: **those containment lists do not
mention `.floating-window-overlay--modal`.** If mobile horizontal-pan
containment is meant to cover modal scrims, the migration may have moved
the scrim out from under its guard. That is a product question for
whoever owns FN-8619, and it is the substance of #2915.
Worth recording: the retired `.agent-detail-overlay { padding: 0;
align-items: stretch }` mobile rule is not a lost feature.
`.floating-window-overlay` is `position: fixed; inset: 0` with no flex
context, so those declarations have nothing to act on — FloatingWindow
positions the panel by geometry instead.
**Verified:** 22/22 in this file, `tsc -p tsconfig.app.json` 0 errors,
lint clean, FNXC gate exit 0. Test-only, no changeset.
---------
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
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