Defect: RA-001: Method Picker Allows Background Page Scroll

[eviltester]

Parent testing issue: #1

Source defect report: https://github.com/eviltester/anywaydata-ai-testing/blob/main/docs/testing/20260625/issue-230-001/defects/RA-001-method-picker-background-scroll.md
Testing artifact folder: https://github.com/eviltester/anywaydata-ai-testing/tree/main/docs/testing/20260625/issue-230-001
Original grid-table-editor story: eviltester/grid-table-editor#230
Original grid-table-editor PR: eviltester/grid-table-editor#247

The detailed defect report from the testing artifact is copied below.

---

RA-001: Method Picker Allows Background Page Scroll

Severity: Medium

Environment: https://eviltester.github.io/grid-table-editor/generator.html, branch codex/230-method-picker-mvc, commit 04570e0e428d.

Steps:

1. Open generator.html.
2. Change the first schema row field type to domain.
3. Open the method picker from Select domain command.
4. Keep focus in the Filter methods search box.
5. Press PageDown.

Observed:

window.scrollY moved from 0 to 290 while the modal remained open. The modal stayed fixed, but the underlying page scrolled behind it.

Expected:

Background page scroll should be locked while the modal is open, or PageDown should be contained within the active modal/list region.

Evidence:

• screenshots/responsive-a11y-background-scroll-page-down.png
• logs/responsive-accessibility-test-log.md

[eviltester]

Implemented the scrolling fix in eviltester/grid-table-editor and published the branch to the test environment.

What changed:

• The method picker compatibility service now locks document/body scrolling while the dialog is open, preserving and restoring the previous overflow styles on close.
• The lock is owned by the document-level modal service, keeping the component-backed method picker itself root-scoped.
• Storybook cleanup now releases the method picker scroll lock if a story is changed while an overlay is still present.
• Added regression coverage for normal close restoration, Storybook stale-overlay cleanup, and the generator browser path where pressing PageDown in the method picker must not move window.scrollY.

Commit: eviltester/grid-table-editor@0d77775

Verification passed:

• Focused Jest for method picker modal + Storybook cleanup
• Focused Playwright regression for generator method picker PageDown scrolling
• pnpm run verify:ui
• pnpm run verify:local
• Push hook verification also passed while publishing the commit

Published to test environment from branch codex/230-method-picker-mvc.
Test environment: https://eviltester.github.io/grid-table-editor/
Deploy run: https://github.com/eviltester/grid-table-editor/actions/runs/28227542250