## Third file, same root cause
The largest block in the dashboard `app:backfill 2/4` shard — and the
same defect as #2885 and #2890.
**Probed before converting, not pattern-matched:**
```
PROBE container=false document=true
```
`TaskDetailModal` mounts through `createPortal`, so its subtree hangs
off `document.body` rather than the container `render()` returns. All
**25** container-rooted lookups in this file could only ever return
null.
## The regex handles two shapes separately, on purpose
`X.container.querySelector` (render-result-scoped) and a bare
destructured `container.querySelector` are converted in separate passes,
because a blanket replace on the previous file rewrote the former into
`renderResult.document...` — not a thing — and broke two passing tests.
A lookbehind keeps `triageContainer.` / `todoContainer.` out of the bare
pass.
## One case needed more than a query-root swap
`does NOT show Changes tab for triage/todo tasks` renders the triage
modal and the todo modal back to back and told them apart by their
container handles. **Both were empty**, so
`querySelectorAll(".detail-tab")` returned `[]` and the assertion
compared `[]` against twelve tab labels — it could not have failed for
the reason it was written.
Querying `document` alone does **not** fix that one: with two modals
mounted at once, a document-rooted `.detail-tab` lookup returns *both*
tab strips concatenated. Unmounting the first render is what makes each
assertion about one modal again.
Verified by measurement rather than reasoning — the file only reached
66/66 after the unmount, not after the query swap.
## Evidence
| | result |
|---|---|
| the file | **66/66** (was 12 failed) |
| shard `2/4` | **22 → 10** |
| mutation: rename `.detail-spec-edit-trigger` in `TaskDetailModal` |
**1 failed** |
`pnpm lint` clean. Test-only; `TaskDetailModal.tsx` restored clean.
## Running total on the portal defect
| PR | file | cleared |
|---|---|---|
| #2885 | `TaskDetailModal.models-progress-workflow` | 30 |
| #2890 | `settings-mobile` | 17 |
| this | `TaskDetailModal.definition-actions` | 12 |
**59 of the ~111 backfill failures**, all one defect: tests querying
`container` for components that render through a portal. It hid because
`screen.*` queries in the same files always worked (they query the
document), so the failures read as "the component never rendered" rather
than "we asked the wrong root".
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
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