cyberflow · cyberflow · Jul 2, 2026 · Jul 2, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -8,6 +8,7 @@ development artifact builds use `vMAJOR.MINOR.PATCH-dev.N`.
 
 ## Unreleased
 
+- Added a collapsible Notation track in the main timeline, collapsed by default and saved per project.
 - Changed notation harmony entry so beat slashes are selectable and Cmd+K opens chord input for the selected beat.
 - Added notation measure range selection with Shift-click, Cmd+C/Cmd+V measure copy and replace-paste for harmony contents, and Esc to clear the selection.
 - Improved notation measure range selection so adjacent selected measures draw as one continuous frame.

diff --git a/JammLab/DesignSystem/AppTheme.swift b/JammLab/DesignSystem/AppTheme.swift
@@ -255,6 +255,7 @@ enum AppTheme {
         static let tempoTrackHeight: CGFloat = 38
         static let waveformTrackHeight: CGFloat = 110
         static let notationTrackHeight: CGFloat = 124
+        static let notationTrackCollapsedHeight: CGFloat = 36
         static let notationMaximumVisibleMeasureCount = 8
         static let notationMeasureMinWidth: CGFloat = 148
         static let notationStaffLineSpacing: CGFloat = 8
@@ -288,8 +289,14 @@ enum AppTheme {
         static var zoomableUpperTrackStackHeight: CGFloat {
             regionTrackHeight + markerTrackHeight + tempoTrackHeight + waveformTrackHeight
         }
+        static func notationTrackCurrentHeight(isCollapsed: Bool) -> CGFloat {
+            isCollapsed ? notationTrackCollapsedHeight : notationTrackHeight
+        }
+        static func upperTrackStackHeight(isNotationTrackCollapsed: Bool) -> CGFloat {
+            zoomableUpperTrackStackHeight + notationTrackCurrentHeight(isCollapsed: isNotationTrackCollapsed)
+        }
         static var upperTrackStackHeight: CGFloat {
-            zoomableUpperTrackStackHeight + notationTrackHeight
+            upperTrackStackHeight(isNotationTrackCollapsed: false)
         }
         static func stemTracksHeight(rowCount: Int) -> CGFloat {
             let visibleRows = max(defaultVisibleStemRows, rowCount)
@@ -299,8 +306,10 @@ enum AppTheme {
         static var stemTracksHeight: CGFloat {
             stemTracksHeight(rowCount: defaultVisibleStemRows)
         }
-        static func tracksMinimumHeight(stemRowCount: Int) -> CGFloat {
-            upperTrackStackHeight + trackSpacing + stemTracksHeight(rowCount: stemRowCount)
+        static func tracksMinimumHeight(stemRowCount: Int, isNotationTrackCollapsed: Bool = false) -> CGFloat {
+            upperTrackStackHeight(isNotationTrackCollapsed: isNotationTrackCollapsed)
+                + trackSpacing
+                + stemTracksHeight(rowCount: stemRowCount)
         }
         static var tracksMinimumHeight: CGFloat {
             tracksMinimumHeight(stemRowCount: defaultVisibleStemRows)
@@ -309,14 +318,26 @@ enum AppTheme {
         static var trackControlsMinimumHeight: CGFloat {
             tracksMinimumHeight
         }
-        static func timelineBlockMinimumHeight(stemRowCount: Int) -> CGFloat {
-            tracksMinimumHeight(stemRowCount: stemRowCount) + viewportFooterGap + viewportControlBarHeight
+        static func timelineBlockMinimumHeight(
+            stemRowCount: Int,
+            isNotationTrackCollapsed: Bool = false
+        ) -> CGFloat {
+            tracksMinimumHeight(
+                stemRowCount: stemRowCount,
+                isNotationTrackCollapsed: isNotationTrackCollapsed
+            ) + viewportFooterGap + viewportControlBarHeight
         }
         static var timelineBlockMinimumHeight: CGFloat {
             timelineBlockMinimumHeight(stemRowCount: defaultVisibleStemRows)
         }
-        static func minimumContentHeight(stemRowCount: Int) -> CGFloat {
-            timelineBlockMinimumHeight(stemRowCount: stemRowCount)
+        static func minimumContentHeight(
+            stemRowCount: Int,
+            isNotationTrackCollapsed: Bool = false
+        ) -> CGFloat {
+            timelineBlockMinimumHeight(
+                stemRowCount: stemRowCount,
+                isNotationTrackCollapsed: isNotationTrackCollapsed
+            )
         }
         static var minimumContentHeight: CGFloat {
             timelineBlockMinimumHeight

diff --git a/JammLab/Models/JammLabProject.swift b/JammLab/Models/JammLabProject.swift
@@ -40,6 +40,7 @@ struct JammLabProject: Codable {
     var timelineVisibleRange: ProjectTimelineVisibleRange?
     var stemState: StemProjectState?
     var isVideoWindowOpen: Bool?
+    var isNotationTrackCollapsed: Bool?
 
     init(
         formatVersion: Int = 10,
@@ -66,7 +67,8 @@ struct JammLabProject: Codable {
         playbackMarkerTime: TimeInterval? = nil,
         timelineVisibleRange: ProjectTimelineVisibleRange? = nil,
         stemState: StemProjectState? = nil,
-        isVideoWindowOpen: Bool? = nil
+        isVideoWindowOpen: Bool? = nil,
+        isNotationTrackCollapsed: Bool? = nil
     ) {
         self.formatVersion = formatVersion
         self.audioBookmarkData = audioBookmarkData
@@ -93,6 +95,7 @@ struct JammLabProject: Codable {
         self.timelineVisibleRange = timelineVisibleRange
         self.stemState = stemState
         self.isVideoWindowOpen = isVideoWindowOpen
+        self.isNotationTrackCollapsed = isNotationTrackCollapsed
     }
 
     private enum CodingKeys: String, CodingKey {
@@ -121,6 +124,7 @@ struct JammLabProject: Codable {
         case timelineVisibleRange
         case stemState
         case isVideoWindowOpen
+        case isNotationTrackCollapsed
     }
 
     init(from decoder: Decoder) throws {
@@ -150,6 +154,7 @@ struct JammLabProject: Codable {
         timelineVisibleRange = try container.decodeIfPresent(ProjectTimelineVisibleRange.self, forKey: .timelineVisibleRange)
         stemState = try container.decodeIfPresent(StemProjectState.self, forKey: .stemState)
         isVideoWindowOpen = try container.decodeIfPresent(Bool.self, forKey: .isVideoWindowOpen)
+        isNotationTrackCollapsed = try container.decodeIfPresent(Bool.self, forKey: .isNotationTrackCollapsed)
     }
 
     func encode(to encoder: Encoder) throws {
@@ -179,6 +184,7 @@ struct JammLabProject: Codable {
         try container.encodeIfPresent(timelineVisibleRange, forKey: .timelineVisibleRange)
         try container.encodeIfPresent(stemState, forKey: .stemState)
         try container.encodeIfPresent(isVideoWindowOpen, forKey: .isVideoWindowOpen)
+        try container.encodeIfPresent(isNotationTrackCollapsed, forKey: .isNotationTrackCollapsed)
     }
 
     func resolvedAudioURL() throws -> URL {

diff --git a/JammLab/Models/ProjectEditableState.swift b/JammLab/Models/ProjectEditableState.swift
@@ -40,4 +40,5 @@ struct ProjectPersistedEditableState: Equatable {
     var playbackMarkerTime: TimeInterval
     var timelineVisibleRange: ClosedRange<TimeInterval>
     var isVideoWindowOpen: Bool
+    var isNotationTrackCollapsed: Bool
 }
diff --git a/JammLab/Services/ProjectPersistenceCoordinator.swift b/JammLab/Services/ProjectPersistenceCoordinator.swift
@@ -48,6 +48,7 @@ struct ProjectDocumentSnapshot {
     let timelineVisibleRange: ClosedRange<TimeInterval>
     let stemState: StemProjectState?
     let isVideoWindowOpen: Bool
+    let isNotationTrackCollapsed: Bool
 }
 
 struct ProjectPersistenceCoordinator {
@@ -227,7 +228,8 @@ struct ProjectPersistenceCoordinator {
                 ProjectStateNormalizer.normalizedTimelineVisibleRange(snapshot.timelineVisibleRange, duration: snapshot.duration)
             ),
             stemState: snapshot.stemState,
-            isVideoWindowOpen: snapshot.importedFile.mediaKind == .video ? snapshot.isVideoWindowOpen : nil
+            isVideoWindowOpen: snapshot.importedFile.mediaKind == .video ? snapshot.isVideoWindowOpen : nil,
+            isNotationTrackCollapsed: snapshot.isNotationTrackCollapsed
         )
     }
 

diff --git a/JammLab/ViewModels/AudioPlayerViewModel+Project.swift b/JammLab/ViewModels/AudioPlayerViewModel+Project.swift
@@ -130,6 +130,7 @@ extension AudioPlayerViewModel {
         isLooping = false
         isClickEnabled = false
         isSnapEnabled = false
+        isNotationTrackCollapsed = true
         mainTrackVolume = AppSliderDefaults.mainTrackVolume
         clickVolume = AppSliderDefaults.clickVolume
         errorMessage = nil
@@ -184,6 +185,7 @@ extension AudioPlayerViewModel {
         timelineVisibleRange = 0...file.duration
         userTimelineVisibleRange = timelineVisibleRange
         playbackState = .stopped
+        isNotationTrackCollapsed = true
         resetStemState()
         isImporting = false
     }
@@ -274,6 +276,7 @@ extension AudioPlayerViewModel {
             restorePlaybackMode(restoredPlaybackMode, preservedTime: currentTime)
             setPlaybackMarkerExactly(to: restoredPlaybackMarkerTime)
             restoreVideoWindowOpenState(file.mediaKind == .video && project.isVideoWindowOpen == true)
+            isNotationTrackCollapsed = project.isNotationTrackCollapsed ?? true
             isImporting = false
             clearUndoHistory()
             markProjectClean()
@@ -393,7 +396,8 @@ extension AudioPlayerViewModel {
             playbackMarkerTime: playbackMarkerTime,
             timelineVisibleRange: userTimelineVisibleRange,
             stemState: makeStemProjectState(),
-            isVideoWindowOpen: isVideoWindowOpen
+            isVideoWindowOpen: isVideoWindowOpen,
+            isNotationTrackCollapsed: isNotationTrackCollapsed
         )
     }
 

diff --git a/JammLab/ViewModels/AudioPlayerViewModel+UndoDirty.swift b/JammLab/ViewModels/AudioPlayerViewModel+UndoDirty.swift
@@ -47,7 +47,8 @@ extension AudioPlayerViewModel {
             isSnapEnabled: isSnapEnabled,
             playbackMarkerTime: ProjectStateNormalizer.normalizedTimelineTime(playbackMarkerTime, duration: duration),
             timelineVisibleRange: ProjectStateNormalizer.normalizedTimelineVisibleRange(userTimelineVisibleRange, duration: duration),
-            isVideoWindowOpen: importedFile?.mediaKind == .video && isVideoWindowOpen
+            isVideoWindowOpen: importedFile?.mediaKind == .video && isVideoWindowOpen,
+            isNotationTrackCollapsed: isNotationTrackCollapsed
         )
     }
 
@@ -121,6 +122,12 @@ extension AudioPlayerViewModel {
         }
     }
 
+    func setNotationTrackCollapsed(_ isCollapsed: Bool) {
+        guard isNotationTrackCollapsed != isCollapsed else { return }
+        isNotationTrackCollapsed = isCollapsed
+        refreshProjectModifiedState()
+    }
+
     func registerUndoState(_ state: ProjectEditableState, actionName: String) {
         guard !isRestoringUndoState, let undoManager else { return }
 

diff --git a/JammLab/ViewModels/AudioPlayerViewModel.swift b/JammLab/ViewModels/AudioPlayerViewModel.swift
@@ -62,6 +62,7 @@ final class AudioPlayerViewModel: ObservableObject {
     @Published var isClickEnabled = false
     @Published var isSnapEnabled = false
     @Published var isVideoWindowOpen = false
+    @Published var isNotationTrackCollapsed = true
     @Published var mainTrackVolume: Float = AppSliderDefaults.mainTrackVolume
     @Published var clickVolume: Float = AudioPlayerViewModel.restoredClickVolume()
     @Published var undoStateRevision = 0

diff --git a/JammLab/Views/Components/ControlHelpText.swift b/JammLab/Views/Components/ControlHelpText.swift
@@ -31,6 +31,8 @@ enum ControlHelpText {
     static let timelinePanRight = "Move timeline right"
     static let timelineZoomIn = "Zoom in"
     static let timelineZoomOut = "Zoom out"
+    static let expandNotationTrack = "Expand Notation track"
+    static let collapseNotationTrack = "Collapse Notation track"
 
     static let resetThemeColors = "Reset theme colors to defaults"
     static let resetClickDefaults = "Restore the current built-in click sound: 1760/1120 Hz and 36/26 ms."

diff --git a/JammLab/Views/Components/TimelineViewportControlBar.swift b/JammLab/Views/Components/TimelineViewportControlBar.swift
@@ -54,7 +54,6 @@ struct TimelineViewportControlBar: View {
     let onPanRight: () -> Void
     let onZoomIn: () -> Void
     let onZoomOut: () -> Void
-    @Environment(\.appColors) private var appColors
 
     var body: some View {
         HStack(spacing: AppTheme.Spacing.md) {
@@ -69,22 +68,51 @@ struct TimelineViewportControlBar: View {
             .frame(height: AppTheme.Timeline.viewportControlBarHeight)
 
             HStack(spacing: AppTheme.Spacing.xs) {
-                viewportButton(systemName: "chevron.left", helpText: ControlHelpText.timelinePanLeft, action: onPanLeft)
-                viewportButton(systemName: "chevron.right", helpText: ControlHelpText.timelinePanRight, action: onPanRight)
-                viewportButton(systemName: "plus", helpText: ControlHelpText.timelineZoomIn, action: onZoomIn)
-                viewportButton(systemName: "minus", helpText: ControlHelpText.timelineZoomOut, action: onZoomOut)
+                TimelineIconButton(systemName: "chevron.left", helpText: ControlHelpText.timelinePanLeft, action: onPanLeft)
+                TimelineIconButton(systemName: "chevron.right", helpText: ControlHelpText.timelinePanRight, action: onPanRight)
+                TimelineIconButton(systemName: "plus", helpText: ControlHelpText.timelineZoomIn, action: onZoomIn)
+                TimelineIconButton(systemName: "minus", helpText: ControlHelpText.timelineZoomOut, action: onZoomOut)
             }
         }
         .frame(height: AppTheme.Timeline.viewportControlBarHeight)
         .disabled(duration <= 0)
         .opacity(duration > 0 ? 1 : 0.45)
     }
+}
 
-    private func viewportButton(
+struct TimelineIconButton: View {
+    let systemName: String
+    let helpText: String
+    let accessibilityLabel: String?
+    let accessibilityValue: String?
+    let action: () -> Void
+    @Environment(\.appColors) private var appColors
+
+    init(
         systemName: String,
         helpText: String,
+        accessibilityLabel: String? = nil,
+        accessibilityValue: String? = nil,
         action: @escaping () -> Void
-    ) -> some View {
+    ) {
+        self.systemName = systemName
+        self.helpText = helpText
+        self.accessibilityLabel = accessibilityLabel
+        self.accessibilityValue = accessibilityValue
+        self.action = action
+    }
+
+    var body: some View {
+        if let accessibilityLabel {
+            baseButton
+                .accessibilityLabel(accessibilityLabel)
+                .accessibilityValue(accessibilityValue ?? "")
+        } else {
+            baseButton
+        }
+    }
+
+    private var baseButton: some View {
         Button(action: action) {
             Image(systemName: systemName)
                 .font(.system(size: 10, weight: .semibold))
@@ -99,6 +127,7 @@ struct TimelineViewportControlBar: View {
                     RoundedRectangle(cornerRadius: AppTheme.Timeline.viewportControlButtonRadius, style: .continuous)
                         .stroke(appColors.border, lineWidth: AppTheme.Stroke.thin)
                 }
+                .contentShape(Rectangle())
         }
         .buttonStyle(.plain)
         .help(helpText)

diff --git a/JammLab/Views/MainWorkspacePanels.swift b/JammLab/Views/MainWorkspacePanels.swift
@@ -107,7 +107,10 @@ extension ContentView {
     }
 
     var timelineTracksHeight: CGFloat {
-        AppTheme.Timeline.tracksMinimumHeight(stemRowCount: timelineStemRowCount)
+        AppTheme.Timeline.tracksMinimumHeight(
+            stemRowCount: timelineStemRowCount,
+            isNotationTrackCollapsed: viewModel.isNotationTrackCollapsed
+        )
     }
 
     var timelineMinimumContentHeight: CGFloat {
@@ -137,6 +140,7 @@ extension ContentView {
             selectedRegionID: viewModel.selectedRegionID,
             beatGrid: beatGrid,
             notationViewport: notationViewportState(availableWidth: notationTrackContentWidth),
+            isNotationTrackCollapsed: viewModel.isNotationTrackCollapsed,
             isLoadingPeakform: viewModel.isBuildingWaveform,
             mainTrackVolume: viewModel.mainTrackVolume,
             playbackMode: viewModel.playbackMode,
@@ -184,7 +188,6 @@ extension ContentView {
         TimelineViewActions(
             locatePlaybackMarker: { viewModel.locatePlaybackMarker(to: $0) },
             addNote: { viewModel.addNote(at: $0) },
-            harmonyInputResolutionChanged: { viewModel.setHarmonyInputResolutionDenominator($0) },
             selectHarmony: { viewModel.selectHarmonySymbol(id: $0) },
             selectNotationMeasure: { viewModel.selectNotationMeasure($0, extendingSelection: $1) },
             selectNotationBeat: { viewModel.selectNotationBeat($0) },
@@ -207,6 +210,7 @@ extension ContentView {
             loopRegionChanged: { viewModel.updateLoopRegion(start: $0, end: $1) },
             timelineScroll: { viewModel.handleTimelineScroll(deltaX: $0, deltaY: $1, anchorTime: $2) },
             mainTrackVolumeChanged: { viewModel.setMainTrackVolume($0) },
+            notationTrackCollapsedChanged: { viewModel.setNotationTrackCollapsed($0) },
             showNotationWindow: { openWindow(id: AppWindowID.notation) }
         )
     }