[rowmanempire]

Summary

Adds an optional MapLayerOptions.offlineMode flag so desktop apps can keep the Map Layers widget visible while offline instead of hiding it.

Today iTwin Studio hides the widget when offline, because attach, base map provider change, sign-in and map settings need the network. With offlineMode: true:

Kept	Hidden / disabled
Map layers on/off switch	Attach layer buttons
Layer visibility, Show all / Hide all / Invert	Map settings popup
Base map visibility, transparency, color	Base map provider select (disabled)
Layer transparency, Zoom to layer, sub-layer visibility	Detach (toolbar, checkboxes, layer menu)
	Sign-in (RequireAuth) buttons
	Drag reorder

Map layer sources (MapLayerSources.create, MapLayerPreferences.getSources) are not loaded in offline mode; they load again when the flag switches back to false.

Compatibility

offlineMode is optional and defaults to false; no existing behavior, props or exports change. A test covers that all actions are still shown when it is not set.

Usage

<MapLayersWidget mapLayerOptions={{ offlineMode: !isOnline }} />

Open question

Should offline mode allow switching the base map to "Color fill" (works offline)? This PR disables the provider select entirely to keep the change minimal.

Testing

• New tests in MapLayerManager.test.tsx (offline mode: hidden actions, layer menu, visibility controls, no source loading, default unchanged).
• pnpm build, pnpm test, pnpm lint, pnpm format, cspell pass locally.

[CLAassistant]

All committers have signed the CLA.

[Copilot]

🟡 Changes recommended

An in-flight source request can continue after switching to read-only mode, violating the offline-loading guarantee.

4 open findings

• Cancel pending source requests when switching to read-only mode · New
• Correct release note to specify provider-only base-map restriction · New
• Test omitted readOnly option to verify default behavior · New
• Clarify read-only base-map editing restrictions in API documentation · New

What changed in this PR

Adds an optional read-only mode to keep Map Layers usable offline while preventing network-dependent configuration changes.

Changes:

• Hides or disables attach, detach, sign-in, reorder, settings, and provider controls.
• Preserves visibility, transparency, zoom, color, and sub-layer controls.
• Skips source loading and adds read-only tests and documentation.

File	Description
MapLayersList.tsx	Hides attach controls.
MapLayerSettingsMenu.tsx	Hides detach action.
MapLayerManager.tsx	Propagates read-only state.
MapLayerItem.tsx	Hides selection and authentication controls.
MapLayerDroppable.tsx	Disables reordering and attachment.
MapLayerActionButtons.tsx	Hides selection and bulk detach.
BasemapPanel.tsx	Disables provider selection.
Interfaces.ts	Defines the public option.
useMapLayerSources.ts	Skips source loading.
MapLayerManager.test.tsx	Tests read-only behavior.
Changeset	Documents the new option.

🧠 Review effort: Balanced

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[mdastous-bentley]

 readOnly  is understandable, but a bit misleading: the widget still lets users change map-layer visibility, transparency, and other display state. “Read-only” usually suggests no changes at all.

offlineMode is a reasonable alternative if the intent is specifically to support offline apps, though it describes the use case rather than the behavior.

[rowmanempire]

@mdastous-bentley Good point