refactor(web): Clarify property names in Timeline and Scrubber

Renamed properties across Timeline/Scrubber components for clarity:
  - scrubOverallPercent → timelineScrollPercent
  - scrubberMonthPercent → viewportTopMonthScrollPercent
  - scrubberMonth → viewportTopMonth
  - leadout → isInLeadOutSection

  Additional changes:
  - Updated ScrubberListener signature to accept object parameter
  - Added detailed JSDoc comments for all Scrubber props
  - Fixed callback invocations to use new object syntax
  - Aligned Timeline's local state variables with Scrubber prop names

mobile/lib/presentation/widgets/action_buttons/unstack_action_button.widget.dart

@@ -36,7 +36,7 @@ class UnStackActionButton extends ConsumerWidget {
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     return BaseActionButton(
-      iconData: Icons.filter_none_rounded,
+      iconData: Icons.layers_clear_outlined,
       label: "unstack".t(context: context),
       onPressed: () => _onTap(context, ref),
     );

mobile/lib/presentation/widgets/asset_viewer/bottom_sheet.widget.dart

@@ -51,6 +51,7 @@ class AssetDetailBottomSheet extends ConsumerWidget {
       isArchived: isArchived,
       isTrashEnabled: isTrashEnable,
       isInLockedView: isInLockedView,
+      isStacked: asset.hasRemote && (asset as RemoteAsset).stackId != null,
       currentAlbum: currentAlbum,
       advancedTroubleshooting: advancedTroubleshooting,
       source: ActionSource.viewer,

mobile/lib/presentation/widgets/asset_viewer/top_app_bar.widget.dart

@@ -57,7 +57,7 @@ class ViewerTopAppBar extends ConsumerWidget implements PreferredSizeWidget {
     final isCasting = ref.watch(castProvider.select((c) => c.isCasting));
 
     final actions = <Widget>[
-      if (asset.hasRemote) const DownloadActionButton(source: ActionSource.viewer, menuItem: true),
+      if (asset.isRemoteOnly) const DownloadActionButton(source: ActionSource.viewer, menuItem: true),
       if (isCasting || (asset.hasRemote)) const CastActionButton(menuItem: true),
       if (album != null && album.isActivityEnabled && album.isShared)
         IconButton(

mobile/lib/presentation/widgets/bottom_sheet/archive_bottom_sheet.widget.dart

@@ -13,6 +13,7 @@ import 'package:immich_mobile/presentation/widgets/action_buttons/share_link_act
 import 'package:immich_mobile/presentation/widgets/action_buttons/stack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/trash_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/unarchive_action_button.widget.dart';
+import 'package:immich_mobile/presentation/widgets/action_buttons/unstack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/upload_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/bottom_sheet/base_bottom_sheet.widget.dart';
 import 'package:immich_mobile/providers/server_info.provider.dart';
@@ -44,6 +45,7 @@ class ArchiveBottomSheet extends ConsumerWidget {
           const EditLocationActionButton(source: ActionSource.timeline),
           const MoveToLockFolderActionButton(source: ActionSource.timeline),
           if (multiselect.selectedAssets.length > 1) const StackActionButton(source: ActionSource.timeline),
+          if (multiselect.hasStacked) const UnStackActionButton(source: ActionSource.timeline),
         ],
         if (multiselect.hasLocal) ...[
           const DeleteLocalActionButton(source: ActionSource.timeline),

mobile/lib/presentation/widgets/bottom_sheet/favorite_bottom_sheet.widget.dart

@@ -13,6 +13,7 @@ import 'package:immich_mobile/presentation/widgets/action_buttons/share_link_act
 import 'package:immich_mobile/presentation/widgets/action_buttons/stack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/trash_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/unfavorite_action_button.widget.dart';
+import 'package:immich_mobile/presentation/widgets/action_buttons/unstack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/upload_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/bottom_sheet/base_bottom_sheet.widget.dart';
 import 'package:immich_mobile/providers/server_info.provider.dart';
@@ -44,6 +45,7 @@ class FavoriteBottomSheet extends ConsumerWidget {
           const EditLocationActionButton(source: ActionSource.timeline),
           const MoveToLockFolderActionButton(source: ActionSource.timeline),
           if (multiselect.selectedAssets.length > 1) const StackActionButton(source: ActionSource.timeline),
+          if (multiselect.hasStacked) const UnStackActionButton(source: ActionSource.timeline),
         ],
         if (multiselect.hasLocal) ...[
           const DeleteLocalActionButton(source: ActionSource.timeline),

mobile/lib/presentation/widgets/bottom_sheet/general_bottom_sheet.widget.dart

@@ -20,6 +20,7 @@ import 'package:immich_mobile/presentation/widgets/action_buttons/share_action_b
 import 'package:immich_mobile/presentation/widgets/action_buttons/share_link_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/stack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/trash_action_button.widget.dart';
+import 'package:immich_mobile/presentation/widgets/action_buttons/unstack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/upload_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/album/album_selector.widget.dart';
 import 'package:immich_mobile/presentation/widgets/bottom_sheet/base_bottom_sheet.widget.dart';
@@ -117,6 +118,7 @@ class _GeneralBottomSheetState extends ConsumerState<GeneralBottomSheet> {
           const EditLocationActionButton(source: ActionSource.timeline),
           const MoveToLockFolderActionButton(source: ActionSource.timeline),
           if (multiselect.selectedAssets.length > 1) const StackActionButton(source: ActionSource.timeline),
+          if (multiselect.hasStacked) const UnStackActionButton(source: ActionSource.timeline),
           const DeleteActionButton(source: ActionSource.timeline),
         ],
         if (multiselect.hasLocal || multiselect.hasMerged) const DeleteLocalActionButton(source: ActionSource.timeline),

mobile/lib/presentation/widgets/bottom_sheet/remote_album_bottom_sheet.widget.dart

@@ -17,6 +17,7 @@ import 'package:immich_mobile/presentation/widgets/action_buttons/share_action_b
 import 'package:immich_mobile/presentation/widgets/action_buttons/share_link_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/stack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/trash_action_button.widget.dart';
+import 'package:immich_mobile/presentation/widgets/action_buttons/unstack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/upload_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/album/album_selector.widget.dart';
 import 'package:immich_mobile/presentation/widgets/bottom_sheet/base_bottom_sheet.widget.dart';
@@ -102,6 +103,7 @@ class _RemoteAlbumBottomSheetState extends ConsumerState<RemoteAlbumBottomSheet>
           const EditLocationActionButton(source: ActionSource.timeline),
           const MoveToLockFolderActionButton(source: ActionSource.timeline),
           if (multiselect.selectedAssets.length > 1) const StackActionButton(source: ActionSource.timeline),
+          if (multiselect.hasStacked) const UnStackActionButton(source: ActionSource.timeline),
         ],
         if (multiselect.hasLocal) ...[
           const DeleteLocalActionButton(source: ActionSource.timeline),

mobile/lib/presentation/widgets/images/image_provider.dart

@@ -123,28 +123,14 @@ ImageProvider getFullImageProvider(BaseAsset asset, {Size size = const Size(1080
   return provider;
 }
 
-ImageProvider getThumbnailImageProvider({BaseAsset? asset, String? remoteId, Size size = kThumbnailResolution}) {
-  assert(asset != null || remoteId != null, 'Either asset or remoteId must be provided');
-
-  if (remoteId != null) {
-    return RemoteThumbProvider(assetId: remoteId);
-  }
-
-  if (_shouldUseLocalAsset(asset!)) {
+ImageProvider? getThumbnailImageProvider(BaseAsset asset, {Size size = kThumbnailResolution}) {
+  if (_shouldUseLocalAsset(asset)) {
     final id = asset is LocalAsset ? asset.id : (asset as RemoteAsset).localId!;
     return LocalThumbProvider(id: id, size: size, assetType: asset.type);
   }
 
-  final String assetId;
-  if (asset is LocalAsset && asset.hasRemote) {
-    assetId = asset.remoteId!;
-  } else if (asset is RemoteAsset) {
-    assetId = asset.id;
-  } else {
-    throw ArgumentError("Unsupported asset type: ${asset.runtimeType}");
-  }
-
-  return RemoteThumbProvider(assetId: assetId);
+  final assetId = asset is RemoteAsset ? asset.id : (asset as LocalAsset).remoteId;
+  return assetId != null ? RemoteThumbProvider(assetId: assetId) : null;
 }
 
 bool _shouldUseLocalAsset(BaseAsset asset) =>

mobile/lib/presentation/widgets/images/thumbnail.widget.dart

@@ -5,7 +5,6 @@ import 'package:immich_mobile/domain/models/asset/base_asset.model.dart';
 import 'package:immich_mobile/extensions/build_context_extensions.dart';
 import 'package:immich_mobile/extensions/theme_extensions.dart';
 import 'package:immich_mobile/presentation/widgets/images/image_provider.dart';
-import 'package:immich_mobile/presentation/widgets/images/local_image_provider.dart';
 import 'package:immich_mobile/presentation/widgets/images/remote_image_provider.dart';
 import 'package:immich_mobile/presentation/widgets/images/thumb_hash_provider.dart';
 import 'package:immich_mobile/presentation/widgets/timeline/constants.dart';
@@ -39,14 +38,7 @@ class Thumbnail extends StatefulWidget {
          ),
          _ => null,
        },
-       imageProvider = switch (asset) {
-         RemoteAsset() =>
-           asset.localId == null
-               ? RemoteThumbProvider(assetId: asset.id)
-               : LocalThumbProvider(id: asset.localId!, size: size, assetType: asset.type),
-         LocalAsset() => LocalThumbProvider(id: asset.id, size: size, assetType: asset.type),
-         _ => null,
-       };
+       imageProvider = asset == null ? null : getThumbnailImageProvider(asset, size: size);
 
   @override
   State<Thumbnail> createState() => _ThumbnailState();

mobile/lib/presentation/widgets/images/thumbnail_tile.widget.dart

@@ -54,8 +54,6 @@ class ThumbnailTile extends ConsumerWidget {
           )
         : const BoxDecoration();
 
-    final hasStack = asset is RemoteAsset && asset.stackId != null;
-
     final bool storageIndicator =
         showStorageIndicator ?? ref.watch(settingsProvider.select((s) => s.get(Setting.showStorageIndicator)));
 
@@ -77,21 +75,10 @@ class ThumbnailTile extends ConsumerWidget {
                     child: Thumbnail.fromAsset(asset: asset, size: size),
                   ),
                 ),
-                if (hasStack)
+                if (asset != null)
                   Align(
                     alignment: Alignment.topRight,
-                    child: Padding(
-                      padding: EdgeInsets.only(right: 10.0, top: asset.isVideo ? 24.0 : 6.0),
-                      child: const _TileOverlayIcon(Icons.burst_mode_rounded),
-                    ),
-                  ),
-                if (asset != null && asset.isVideo)
-                  Align(
-                    alignment: Alignment.topRight,
-                    child: Padding(
-                      padding: const EdgeInsets.only(right: 10.0, top: 6.0),
-                      child: _VideoIndicator(asset.duration),
-                    ),
+                    child: _AssetTypeIcons(asset: asset),
                   ),
                 if (storageIndicator && asset != null)
                   switch (asset.storage) {
@@ -214,3 +201,34 @@ class _TileOverlayIcon extends StatelessWidget {
     );
   }
 }
+
+class _AssetTypeIcons extends StatelessWidget {
+  final BaseAsset asset;
+
+  const _AssetTypeIcons({required this.asset});
+
+  @override
+  Widget build(BuildContext context) {
+    final hasStack = asset is RemoteAsset && (asset as RemoteAsset).stackId != null;
+    final isLivePhoto = asset is RemoteAsset && asset.livePhotoVideoId != null;
+
+    return Column(
+      mainAxisSize: MainAxisSize.min,
+      crossAxisAlignment: CrossAxisAlignment.end,
+      children: [
+        if (asset.isVideo)
+          Padding(padding: const EdgeInsets.only(right: 10.0, top: 6.0), child: _VideoIndicator(asset.duration)),
+        if (hasStack)
+          const Padding(
+            padding: EdgeInsets.only(right: 10.0, top: 6.0),
+            child: _TileOverlayIcon(Icons.burst_mode_rounded),
+          ),
+        if (isLivePhoto)
+          const Padding(
+            padding: EdgeInsets.only(right: 10.0, top: 6.0),
+            child: _TileOverlayIcon(Icons.motion_photos_on_rounded),
+          ),
+      ],
+    );
+  }
+}

mobile/lib/providers/infrastructure/action.provider.dart

@@ -3,7 +3,10 @@ import 'package:background_downloader/background_downloader.dart';
 import 'package:flutter/material.dart';
 import 'package:immich_mobile/constants/enums.dart';
 import 'package:immich_mobile/domain/models/asset/base_asset.model.dart';
+import 'package:immich_mobile/domain/services/asset.service.dart';
 import 'package:immich_mobile/models/download/livephotos_medatada.model.dart';
+import 'package:immich_mobile/presentation/widgets/asset_viewer/asset_viewer.state.dart';
+import 'package:immich_mobile/providers/infrastructure/asset.provider.dart';
 import 'package:immich_mobile/providers/infrastructure/asset_viewer/current_asset.provider.dart';
 import 'package:immich_mobile/providers/timeline/multiselect.provider.dart';
 import 'package:immich_mobile/providers/user.provider.dart';
@@ -36,6 +39,7 @@ class ActionNotifier extends Notifier<void> {
   late ActionService _service;
   late UploadService _uploadService;
   late DownloadService _downloadService;
+  late AssetService _assetService;
 
   ActionNotifier() : super();
 
@@ -43,6 +47,7 @@ class ActionNotifier extends Notifier<void> {
   void build() {
     _uploadService = ref.watch(uploadServiceProvider);
     _service = ref.watch(actionServiceProvider);
+    _assetService = ref.watch(assetServiceProvider);
     _downloadService = ref.watch(downloadServiceProvider);
     _downloadService.onImageDownloadStatus = _downloadImageCallback;
     _downloadService.onVideoDownloadStatus = _downloadVideoCallback;
@@ -335,6 +340,14 @@ class ActionNotifier extends Notifier<void> {
     final assets = _getOwnedRemoteAssetsForSource(source);
     try {
       await _service.unStack(assets.map((e) => e.stackId).nonNulls.toList());
+      if (source == ActionSource.viewer) {
+        final updatedParent = await _assetService.getRemoteAsset(assets.first.id);
+        if (updatedParent != null) {
+          ref.read(currentAssetNotifier.notifier).setAsset(updatedParent);
+          ref.read(assetViewerProvider.notifier).setAsset(updatedParent);
+        }
+      }
+
       return ActionResult(count: assets.length, success: true);
     } catch (error, stack) {
       _logger.severe('Failed to unstack assets', error, stack);

mobile/lib/providers/timeline/multiselect.provider.dart

@@ -28,6 +28,8 @@ class MultiSelectState {
   bool get hasRemote =>
       selectedAssets.any((asset) => asset.storage == AssetState.remote || asset.storage == AssetState.merged);
 
+  bool get hasStacked => selectedAssets.any((asset) => asset is RemoteAsset && asset.stackId != null);
+
   bool get hasLocal => selectedAssets.any((asset) => asset.storage == AssetState.local);
 
   bool get hasMerged => selectedAssets.any((asset) => asset.storage == AssetState.merged);

mobile/lib/utils/action_button.utils.dart

@@ -16,6 +16,7 @@ import 'package:immich_mobile/presentation/widgets/action_buttons/share_action_b
 import 'package:immich_mobile/presentation/widgets/action_buttons/share_link_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/trash_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/unarchive_action_button.widget.dart';
+import 'package:immich_mobile/presentation/widgets/action_buttons/unstack_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/upload_action_button.widget.dart';
 
 class ActionButtonContext {
@@ -24,6 +25,7 @@ class ActionButtonContext {
   final bool isArchived;
   final bool isTrashEnabled;
   final bool isInLockedView;
+  final bool isStacked;
   final RemoteAlbum? currentAlbum;
   final bool advancedTroubleshooting;
   final ActionSource source;
@@ -33,6 +35,7 @@ class ActionButtonContext {
     required this.isOwner,
     required this.isArchived,
     required this.isTrashEnabled,
+    required this.isStacked,
     required this.isInLockedView,
     required this.currentAlbum,
     required this.advancedTroubleshooting,
@@ -55,6 +58,7 @@ enum ActionButtonType {
   deleteLocal,
   upload,
   removeFromAlbum,
+  unstack,
   likeActivity;
 
   bool shouldShow(ActionButtonContext context) {
@@ -110,6 +114,10 @@ enum ActionButtonType {
         context.isOwner && //
             !context.isInLockedView && //
             context.currentAlbum != null,
+      ActionButtonType.unstack =>
+        context.isOwner && //
+            !context.isInLockedView && //
+            context.isStacked,
       ActionButtonType.likeActivity =>
         !context.isInLockedView &&
             context.currentAlbum != null &&
@@ -138,28 +146,13 @@ enum ActionButtonType {
         source: context.source,
       ),
       ActionButtonType.likeActivity => const LikeActivityActionButton(),
+      ActionButtonType.unstack => UnStackActionButton(source: context.source),
     };
   }
 }
 
 class ActionButtonBuilder {
-  static const List<ActionButtonType> _actionTypes = [
-    ActionButtonType.advancedInfo,
-    ActionButtonType.share,
-    ActionButtonType.shareLink,
-    ActionButtonType.likeActivity,
-    ActionButtonType.archive,
-    ActionButtonType.unarchive,
-    ActionButtonType.download,
-    ActionButtonType.trash,
-    ActionButtonType.deletePermanent,
-    ActionButtonType.delete,
-    ActionButtonType.moveToLockFolder,
-    ActionButtonType.removeFromLockFolder,
-    ActionButtonType.deleteLocal,
-    ActionButtonType.upload,
-    ActionButtonType.removeFromAlbum,
-  ];
+  static const List<ActionButtonType> _actionTypes = ActionButtonType.values;
 
   static List<Widget> build(ActionButtonContext context) {
     return _actionTypes.where((type) => type.shouldShow(context)).map((type) => type.buildButton(context)).toList();

mobile/test/utils/action_button_utils_test.dart

@@ -82,6 +82,7 @@ void main() {
         isInLockedView: false,
         currentAlbum: null,
         advancedTroubleshooting: false,
+        isStacked: false,
         source: ActionSource.timeline,
       );
 
@@ -112,6 +113,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -127,6 +129,7 @@ void main() {
           isInLockedView: true,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -145,6 +148,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -161,6 +165,7 @@ void main() {
           isInLockedView: true,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -177,6 +182,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -195,6 +201,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -211,6 +218,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -227,6 +235,7 @@ void main() {
           isInLockedView: true,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -243,6 +252,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -259,6 +269,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -277,6 +288,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -293,6 +305,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -309,6 +322,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -327,6 +341,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -343,6 +358,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -359,6 +375,7 @@ void main() {
           isInLockedView: true,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -377,6 +394,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -393,6 +411,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -411,6 +430,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -427,6 +447,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -445,6 +466,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -463,6 +485,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -481,6 +504,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -497,6 +521,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -512,6 +537,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -530,6 +556,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -548,6 +575,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: album,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -563,6 +591,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -581,6 +610,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: album,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -597,6 +627,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: album,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -613,6 +644,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: album,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -628,6 +660,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -645,6 +678,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: true,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -660,6 +694,7 @@ void main() {
           isInLockedView: false,
           currentAlbum: null,
           advancedTroubleshooting: false,
+          isStacked: false,
           source: ActionSource.timeline,
         );
 
@@ -668,6 +703,59 @@ void main() {
     });
   });
 
+  group('unstack button', () {
+    test('should show when owner, not locked, has remote, and is stacked', () {
+      final remoteAsset = createRemoteAsset();
+      final context = ActionButtonContext(
+        asset: remoteAsset,
+        isOwner: true,
+        isArchived: false,
+        isTrashEnabled: true,
+        isInLockedView: false,
+        currentAlbum: null,
+        advancedTroubleshooting: false,
+        isStacked: true,
+        source: ActionSource.timeline,
+      );
+
+      expect(ActionButtonType.unstack.shouldShow(context), isTrue);
+    });
+
+    test('should not show when not stacked', () {
+      final remoteAsset = createRemoteAsset();
+      final context = ActionButtonContext(
+        asset: remoteAsset,
+        isOwner: true,
+        isArchived: false,
+        isTrashEnabled: true,
+        isInLockedView: false,
+        currentAlbum: null,
+        advancedTroubleshooting: false,
+        isStacked: false,
+        source: ActionSource.timeline,
+      );
+
+      expect(ActionButtonType.unstack.shouldShow(context), isFalse);
+    });
+
+    test('should not show when not owner', () {
+      final remoteAsset = createRemoteAsset();
+      final context = ActionButtonContext(
+        asset: remoteAsset,
+        isOwner: false,
+        isArchived: true,
+        isTrashEnabled: true,
+        isInLockedView: false,
+        currentAlbum: null,
+        advancedTroubleshooting: false,
+        isStacked: false,
+        source: ActionSource.timeline,
+      );
+
+      expect(ActionButtonType.unstack.shouldShow(context), isFalse);
+    });
+  });
+
   group('ActionButtonType.buildButton', () {
     late BaseAsset asset;
     late ActionButtonContext context;
@@ -682,6 +770,7 @@ void main() {
         isInLockedView: false,
         currentAlbum: null,
         advancedTroubleshooting: false,
+        isStacked: false,
         source: ActionSource.timeline,
       );
     });
@@ -698,6 +787,22 @@ void main() {
             isInLockedView: false,
             currentAlbum: album,
             advancedTroubleshooting: false,
+            isStacked: false,
+            source: ActionSource.timeline,
+          );
+          final widget = buttonType.buildButton(contextWithAlbum);
+          expect(widget, isA<Widget>());
+        } else if (buttonType == ActionButtonType.unstack) {
+          final album = createRemoteAlbum();
+          final contextWithAlbum = ActionButtonContext(
+            asset: asset,
+            isOwner: true,
+            isArchived: false,
+            isTrashEnabled: true,
+            isInLockedView: false,
+            currentAlbum: album,
+            advancedTroubleshooting: false,
+            isStacked: true,
             source: ActionSource.timeline,
           );
           final widget = buttonType.buildButton(contextWithAlbum);
@@ -721,6 +826,7 @@ void main() {
         isInLockedView: false,
         currentAlbum: null,
         advancedTroubleshooting: false,
+        isStacked: false,
         source: ActionSource.timeline,
       );
 
@@ -741,6 +847,7 @@ void main() {
         isInLockedView: false,
         currentAlbum: album,
         advancedTroubleshooting: false,
+        isStacked: false,
         source: ActionSource.timeline,
       );
 
@@ -759,6 +866,7 @@ void main() {
         isInLockedView: false,
         currentAlbum: null,
         advancedTroubleshooting: false,
+        isStacked: false,
         source: ActionSource.timeline,
       );
 
@@ -778,6 +886,7 @@ void main() {
         isInLockedView: false,
         currentAlbum: null,
         advancedTroubleshooting: false,
+        isStacked: false,
         source: ActionSource.timeline,
       );
 
@@ -791,6 +900,7 @@ void main() {
         isInLockedView: false,
         currentAlbum: null,
         advancedTroubleshooting: false,
+        isStacked: false,
         source: ActionSource.timeline,
       );
 

web/src/lib/components/timeline/Scrubber.svelte

@@ -3,7 +3,7 @@
   import type { ScrubberMonth } from '$lib/managers/timeline-manager/types';
   import { mobileDevice } from '$lib/stores/mobile-device.svelte';
   import { getTabbable } from '$lib/utils/focus-util';
-  import { type ScrubberListener } from '$lib/utils/timeline-util';
+  import { type ScrubberListener, type TimelineYearMonth } from '$lib/utils/timeline-util';
   import { Icon } from '@immich/ui';
   import { mdiPlay } from '@mdi/js';
   import { clamp } from 'lodash-es';
@@ -11,18 +11,31 @@
   import { fade, fly } from 'svelte/transition';
 
   interface Props {
+    /** Offset from the top of the timeline (e.g., for headers) */
     timelineTopOffset?: number;
+    /** Offset from the bottom of the timeline (e.g., for footers) */
     timelineBottomOffset?: number;
+    /** Total height of the scrubber component */
     height?: number;
+    /** Timeline manager instance that controls the timeline state */
     timelineManager: TimelineManager;
-    scrubOverallPercent?: number;
-    scrubberMonthPercent?: number;
-    scrubberMonth?: { year: number; month: number };
-    leadout?: boolean;
+    /** Overall scroll percentage through the entire timeline (0-1), used when no specific month is targeted */
+    timelineScrollPercent?: number;
+    /** The percentage of scroll through the month that is currently intersecting the top boundary of the viewport */
+    viewportTopMonthScrollPercent?: number;
+    /** The year/month of the timeline month at the top of the viewport */
+    viewportTopMonth?: TimelineYearMonth;
+    /** Indicates whether the viewport is currently in the lead-out section (after all months) */
+    isInLeadOutSection?: boolean;
+    /** Width of the scrubber component in pixels (bindable for parent component margin adjustments) */
     scrubberWidth?: number;
+    /** Callback fired when user interacts with the scrubber to navigate */
     onScrub?: ScrubberListener;
+    /** Callback fired when keyboard events occur on the scrubber */
     onScrubKeyDown?: (event: KeyboardEvent, element: HTMLElement) => void;
+    /** Callback fired when scrubbing starts */
     startScrub?: ScrubberListener;
+    /** Callback fired when scrubbing stops */
     stopScrub?: ScrubberListener;
   }
 
@@ -31,10 +44,10 @@
     timelineBottomOffset = 0,
     height = 0,
     timelineManager,
-    scrubOverallPercent = 0,
-    scrubberMonthPercent = 0,
-    scrubberMonth = undefined,
-    leadout = false,
+    timelineScrollPercent = 0,
+    viewportTopMonthScrollPercent = 0,
+    viewportTopMonth = undefined,
+    isInLeadOutSection = false,
     onScrub = undefined,
     onScrubKeyDown = undefined,
     startScrub = undefined,
@@ -100,7 +113,7 @@
         offset += scrubberMonthPercent * relativeBottomOffset;
       }
       return offset;
-    } else if (leadout) {
+    } else if (isInLeadOutSection) {
       let offset = relativeTopOffset;
       for (const segment of segments) {
         offset += segment.height;
@@ -111,7 +124,9 @@
       return scrubOverallPercent * (height - (PADDING_TOP + PADDING_BOTTOM));
     }
   };
-  let scrollY = $derived(toScrollFromMonthGroupPercentage(scrubberMonth, scrubberMonthPercent, scrubOverallPercent));
+  let scrollY = $derived(
+    toScrollFromMonthGroupPercentage(viewportTopMonth, viewportTopMonthScrollPercent, timelineScrollPercent),
+  );
   let timelineFullHeight = $derived(timelineManager.scrubberTimelineHeight + timelineTopOffset + timelineBottomOffset);
   let relativeTopOffset = $derived(toScrollY(timelineTopOffset / timelineFullHeight));
   let relativeBottomOffset = $derived(toScrollY(timelineBottomOffset / timelineFullHeight));
@@ -295,12 +310,24 @@
 
     const scrollPercent = toTimelineY(hoverY);
     if (wasDragging === false && isDragging) {
-      void startScrub?.(segmentDate!, scrollPercent, monthGroupPercentY);
-      void onScrub?.(segmentDate!, scrollPercent, monthGroupPercentY);
+      void startScrub?.({
+        scrubberMonth: segmentDate!,
+        overallScrollPercent: scrollPercent,
+        scrubberMonthScrollPercent: monthGroupPercentY,
+      });
+      void onScrub?.({
+        scrubberMonth: segmentDate!,
+        overallScrollPercent: scrollPercent,
+        scrubberMonthScrollPercent: monthGroupPercentY,
+      });
     }
 
     if (wasDragging && !isDragging) {
-      void stopScrub?.(segmentDate!, scrollPercent, monthGroupPercentY);
+      void stopScrub?.({
+        scrubberMonth: segmentDate!,
+        overallScrollPercent: scrollPercent,
+        scrubberMonthScrollPercent: monthGroupPercentY,
+      });
       return;
     }
 
@@ -308,7 +335,11 @@
       return;
     }
 
-    void onScrub?.(segmentDate!, scrollPercent, monthGroupPercentY);
+    void onScrub?.({
+      scrubberMonth: segmentDate!,
+      overallScrollPercent: scrollPercent,
+      scrubberMonthScrollPercent: monthGroupPercentY,
+    });
   };
   /* eslint-disable tscompat/tscompat */
   const getTouch = (event: TouchEvent) => {
@@ -412,7 +443,11 @@
       }
       if (next) {
         event.preventDefault();
-        void onScrub?.({ year: next.year, month: next.month }, -1, 0);
+        void onScrub?.({
+          scrubberMonth: { year: next.year, month: next.month },
+          overallScrollPercent: -1,
+          scrubberMonthScrollPercent: 0,
+        });
         return true;
       }
     }
@@ -422,7 +457,11 @@
         const next = segments[idx + 1];
         if (next) {
           event.preventDefault();
-          void onScrub?.({ year: next.year, month: next.month }, -1, 0);
+          void onScrub?.({
+            scrubberMonth: { year: next.year, month: next.month },
+            overallScrollPercent: -1,
+            scrubberMonthScrollPercent: 0,
+          });
           return true;
         }
       }

web/src/lib/components/timeline/Timeline.svelte

@@ -110,14 +110,19 @@
   let timelineElement: HTMLElement | undefined = $state();
   let showSkeleton = $state(true);
   let isShowSelectDate = $state(false);
-  let scrubberMonthPercent = $state(0);
-  let scrubberMonth: { year: number; month: number } | undefined = $state(undefined);
-  let scrubOverallPercent: number = $state(0);
+  // The percentage of scroll through the month that is currently intersecting the top boundary of the viewport.
+  // Note: There may be multiple months visible within the viewport at any given time.
+  let viewportTopMonthScrollPercent = $state(0);
+  // The timeline month intersecting the top position of the viewport
+  let viewportTopMonth: { year: number; month: number } | undefined = $state(undefined);
+  // Overall scroll percentage through the entire timeline (0-1)
+  let timelineScrollPercent: number = $state(0);
   let scrubberWidth = $state(0);
 
   // 60 is the bottom spacer element at 60px
   let bottomSectionHeight = 60;
-  let leadout = $state(false);
+  // Indicates whether the viewport is currently in the lead-out section (after all months)
+  let isInLeadOutSection = $state(false);
 
   const maxMd = $derived(mobileDevice.maxMd);
   const usingMobileDevice = $derived(mobileDevice.pointerCoarse);
@@ -301,20 +306,19 @@
     scrollTop(scrollToTop);
   };
 
-  // note: don't throttle, debounch, or otherwise make this function async - it causes flicker
-  const onScrub: ScrubberListener = (
-    scrubMonth: { year: number; month: number },
-    overallScrollPercent: number,
-    scrubberMonthScrollPercent: number,
-  ) => {
-    if (!scrubMonth || timelineManager.timelineHeight < timelineManager.viewportHeight * 2) {
+  // note: don't throttle, debounce, or otherwise make this function async - it causes flicker
+  // this function scrolls the timeline to the specified month group and offset, based on scrubber interaction
+  const onScrub: ScrubberListener = (scrubberData) => {
+    const { scrubberMonth, overallScrollPercent, scrubberMonthScrollPercent } = scrubberData;
+
+    if (!scrubberMonth || timelineManager.timelineHeight < timelineManager.viewportHeight * 2) {
       // edge case - scroll limited due to size of content, must adjust - use use the overall percent instead
       const maxScroll = getMaxScroll();
       const offset = maxScroll * overallScrollPercent;
       scrollTop(offset);
     } else {
       const monthGroup = timelineManager.months.find(
-        ({ yearMonth: { year, month } }) => year === scrubMonth.year && month === scrubMonth.month,
+        ({ yearMonth: { year, month } }) => year === scrubberMonth.year && month === scrubberMonth.month,
       );
       if (!monthGroup) {
         return;
@@ -325,7 +329,7 @@
 
   // note: don't throttle, debounch, or otherwise make this function async - it causes flicker
   const handleTimelineScroll = () => {
-    leadout = false;
+    isInLeadOutSection = false;
 
     if (!element) {
       return;
@@ -334,19 +338,19 @@
     if (timelineManager.timelineHeight < timelineManager.viewportHeight * 2) {
       // edge case - scroll limited due to size of content, must adjust -  use the overall percent instead
       const maxScroll = getMaxScroll();
-      scrubOverallPercent = Math.min(1, element.scrollTop / maxScroll);
+      timelineScrollPercent = Math.min(1, element.scrollTop / maxScroll);
 
-      scrubberMonth = undefined;
-      scrubberMonthPercent = 0;
+      viewportTopMonth = undefined;
+      viewportTopMonthScrollPercent = 0;
     } else {
       let top = element.scrollTop;
       if (top < timelineManager.topSectionHeight) {
         // in the lead-in area
-        scrubberMonth = undefined;
-        scrubberMonthPercent = 0;
+        viewportTopMonth = undefined;
+        viewportTopMonthScrollPercent = 0;
         const maxScroll = getMaxScroll();
 
-        scrubOverallPercent = Math.min(1, element.scrollTop / maxScroll);
+        timelineScrollPercent = Math.min(1, element.scrollTop / maxScroll);
         return;
       }
 
@@ -371,15 +375,15 @@
         let next = top - monthGroupHeight * maxScrollPercent;
         // instead of checking for < 0, add a little wiggle room for subpixel resolution
         if (next < -1 && monthGroup) {
-          scrubberMonth = monthGroup;
+          viewportTopMonth = monthGroup;
 
           // allowing next to be at least 1 may cause percent to go negative, so ensure positive percentage
-          scrubberMonthPercent = Math.max(0, top / (monthGroupHeight * maxScrollPercent));
+          viewportTopMonthScrollPercent = Math.max(0, top / (monthGroupHeight * maxScrollPercent));
 
           // compensate for lost precision/rounding errors advance to the next bucket, if present
-          if (scrubberMonthPercent > 0.9999 && i + 1 < monthsLength - 1) {
-            scrubberMonth = timelineManager.months[i + 1].yearMonth;
-            scrubberMonthPercent = 0;
+          if (viewportTopMonthScrollPercent > 0.9999 && i + 1 < monthsLength - 1) {
+            viewportTopMonth = timelineManager.months[i + 1].yearMonth;
+            viewportTopMonthScrollPercent = 0;
           }
 
           found = true;
@@ -388,10 +392,10 @@
         top = next;
       }
       if (!found) {
-        leadout = true;
-        scrubberMonth = undefined;
-        scrubberMonthPercent = 0;
-        scrubOverallPercent = 1;
+        isInLeadOutSection = true;
+        viewportTopMonth = undefined;
+        viewportTopMonthScrollPercent = 0;
+        timelineScrollPercent = 1;
       }
     }
   };
@@ -854,10 +858,10 @@
     height={timelineManager.viewportHeight}
     timelineTopOffset={timelineManager.topSectionHeight}
     timelineBottomOffset={bottomSectionHeight}
-    {leadout}
-    {scrubOverallPercent}
-    {scrubberMonthPercent}
-    {scrubberMonth}
+    {isInLeadOutSection}
+    {timelineScrollPercent}
+    {viewportTopMonthScrollPercent}
+    {viewportTopMonth}
     {onScrub}
     bind:scrubberWidth
     onScrubKeyDown={(evt) => {

web/src/lib/utils/timeline-util.ts

@@ -23,11 +23,11 @@ export type TimelineDateTime = TimelineDate & {
   millisecond: number;
 };
 
-export type ScrubberListener = (
-  scrubberMonth: { year: number; month: number },
-  overallScrollPercent: number,
-  scrubberMonthScrollPercent: number,
-) => void | Promise<void>;
+export type ScrubberListener = (scrubberData: {
+  scrubberMonth: { year: number; month: number };
+  overallScrollPercent: number;
+  scrubberMonthScrollPercent: number;
+}) => void | Promise<void>;
 
 // used for AssetResponseDto.dateTimeOriginal, amongst others
 export const fromISODateTime = (isoDateTime: string, timeZone: string): DateTime<true> =>