[Roman Lutz (romanlutz)]

Description

Switching scenarios in the preset editor could leave the previous scenario and configuration available to Save while the new metadata was loading.

Fixes #3755

Track the selected scenario separately from its resolved metadata. Disable and guard Save until the selected configuration is ready, including programmatic submits fired before React commits the selection change. Ignore outdated metadata responses after another selection or unmount. Failed loads retain the selection and show the existing error UI; already accepted saves are left alone.

This is limited to the selection/save race. Shared preset/form serialization, loaded-list values, and launch behavior are unchanged.

Tests and Documentation

Added focused regressions for pending replacements, direct and same-event submissions, reversed responses, failure/retry, navigation/unmount, accepted saves, and edit-mode list preservation. Updated the GUI documentation to explain loading and failure behavior.

Validation completed on the delivered commit before opening this PR. Commands below ran from frontend.

npm test -- --runInBand --runTestsByPath src\components\ScenarioPresets\ScenarioPresetEditor.test.tsx src\components\ScenarioPresets\scenarioPresetForm.test.ts src\components\Parameters\parameterForm.test.ts src\components\Scenarios\ScenarioDetail.test.tsx --silent

Passed: 4 suites, 287 tests. Includes the existing ScenarioDetail and shared preset/form parameter coverage.

Command	Result
npm run type-check	Passed
npm exec -- tsc --noEmit --project tsconfig.test.json	Passed
npm exec -- eslint src\components\ScenarioPresets\ScenarioPresetEditor.tsx src\components\ScenarioPresets\ScenarioPresetEditor.test.tsx --report-unused-disable-directives --max-warnings 0	Passed
npm run build	Passed; post-commit compatibility stamps match HEAD

npm exec -- playwright test numeric-controls.spec.ts --project mock --workers 1 --grep "scenario steppers|native shared dynamic parameter controls step once" --reporter=list

Passed: 5 existing offline browser tests. A separate offline Chromium check against the built editor also passed at 1440x1000 and 390x844, covering keyboard selection, pending submissions, reversed responses, error retention, and retry. These were fixture-backed browser observations, not live backend saves. All verification helpers are stopped.

JupyText: Not run; the change is frontend-only with a Markdown documentation update.

[Copilot]

🟢 Approval recommended

No active review issues were identified for the change addressing stale-scenario saves in the preset editor.

No open issues 🎉

What changed in this PR

Addresses #3755 by preventing the preset editor from saving the previous scenario’s configuration while a new selection loads.

Changes:

• Tracks the selected scenario separately from loaded metadata, guards submissions, and ignores stale responses.
• Adds regression coverage for selection races, failures and retries, unmounting, accepted saves, and stored list preservation.
• Documents Save availability and failed-load behavior without changing shared serialization or launch behavior.

File	Description
frontend/​src/​components/​ScenarioPresets/​ScenarioPresetEditor.tsx	Adds selection tracking, request guards, and Save readiness checks.
frontend/​src/​components/​ScenarioPresets/​ScenarioPresetEditor.test.tsx	Covers race conditions and preservation of existing save behavior.
doc/​gui/​0_gui.md	Explains loading and failure behavior in the preset editor.

_{Review effort: Balanced}