Subtle selection follow-ups: group header hairline, no focus re-render for legacy rows, cmux.json test

Sources/ContentView.swift

@@ -15862,10 +15862,11 @@ struct TabItemView: View, Equatable {
     // percent here and applying a primitive `.font(...)` keeps magnification
     // working while dropping those per-label modifier bodies.
     @Environment(\.cmuxGlobalFontMagnificationPercent) private var globalFontMagnificationPercent
-    // Window activation and Increase Contrast only: the selection wash dims to
-    // neutral when the window is inactive, like Finder. Neither changes per
-    // keystroke.
-    @Environment(\.controlActiveState) private var controlActiveState
+    // Increase Contrast strengthens the multi-selection and subtle selection
+    // washes; it changes only when the accessibility option does. Window
+    // activation is read by `SidebarSelectionWindowActivationReader`, and
+    // only for subtle-selection rows that are selected, so focus changes
+    // don't invalidate every row.
     @Environment(\.colorSchemeContrast) private var colorSchemeContrast
 #if DEBUG
     // Plain-value environment probe (closure struct, not an object reference):
@@ -16166,10 +16167,6 @@ struct TabItemView: View, Equatable {
 #endif
         let signpost = SidebarProfilingSignposts.begin("sidebar-tab-item-body", "index=\(index) workspace=\(sidebarShortTabId(workspaceId)) active=\(isActive) unread=\(unreadCount)")
         let workspaceSnapshot = self.workspaceSnapshot
-        let rowBackgroundStyle = backgroundStyle(for: workspaceSnapshot)
-        let rowBackgroundColor = rowBackgroundStyle.color.map {
-            Color(nsColor: $0).opacity(rowBackgroundStyle.opacity)
-        } ?? .clear
         let rowRailColor = railColor(for: workspaceSnapshot)
         let accessibilityTitle = workspaceSnapshot.accessibilityLabel(index: index, workspaceCount: accessibilityWorkspaceCount)
         let closeWorkspaceTooltip = String(localized: "sidebar.closeWorkspace.tooltip", defaultValue: "Close Workspace")
@@ -16599,27 +16596,7 @@ struct TabItemView: View, Equatable {
         // they appear; content changes now apply in one discrete layout pass.
         .padding(.horizontal, SidebarWorkspaceListMetrics.rowContentHorizontalPadding)
         .padding(.vertical, 8)
-        .background(
-            RoundedRectangle(cornerRadius: 6)
-                .fill(rowBackgroundColor)
-                .overlay {
-                    RoundedRectangle(cornerRadius: 6)
-                        .strokeBorder(
-                            activeBorderColor(for: rowBackgroundStyle),
-                            lineWidth: activeBorderLineWidth(for: rowBackgroundStyle)
-                        )
-                }
-                .overlay(alignment: .leading) {
-                    if showsLeadingRail(for: workspaceSnapshot) {
-                        Capsule(style: .continuous)
-                        .fill(rowRailColor)
-                            .frame(width: 3)
-                            .padding(.leading, 4)
-                            .padding(.vertical, 5)
-                            .offset(x: -1)
-                    }
-                }
-        )
+        .background(rowBackground(for: workspaceSnapshot, railColor: rowRailColor))
         .sidebarShortcutHintOverlay(
             text: showsWorkspaceShortcutHint ? workspaceShortcutLabel : nil,
             emphasis: shortcutHintEmphasis,
@@ -16719,8 +16696,68 @@ struct TabItemView: View, Equatable {
         isEditing = true
     }
 
+    /// Only a selected row painted with the subtle selection changes with
+    /// window activation. Legacy and unselected rows never read it.
+    private var selectionChromeTracksWindowActivation: Bool {
+        (isActive || isMultiSelected)
+            && sidebarUsesSubtleSelection(
+                activeTabIndicatorStyle: activeTabIndicatorStyle,
+                subtleSelection: settings.subtleSelection,
+                sidebarSelectionColorHex: sidebarSelectionColorHex
+            )
+    }
+
+    @ViewBuilder
+    private func rowBackground(
+        for workspaceSnapshot: SidebarWorkspaceSnapshotBuilder.Snapshot,
+        railColor: Color
+    ) -> some View {
+        if selectionChromeTracksWindowActivation {
+            SidebarSelectionWindowActivationReader { isEmphasized in
+                rowBackgroundShape(
+                    style: backgroundStyle(for: workspaceSnapshot, isEmphasized: isEmphasized),
+                    workspaceSnapshot: workspaceSnapshot,
+                    railColor: railColor
+                )
+            }
+        } else {
+            rowBackgroundShape(
+                style: backgroundStyle(for: workspaceSnapshot, isEmphasized: true),
+                workspaceSnapshot: workspaceSnapshot,
+                railColor: railColor
+            )
+        }
+    }
+
+    private func rowBackgroundShape(
+        style: SidebarWorkspaceRowBackgroundStyle,
+        workspaceSnapshot: SidebarWorkspaceSnapshotBuilder.Snapshot,
+        railColor: Color
+    ) -> some View {
+        RoundedRectangle(cornerRadius: 6)
+            .fill(style.color.map { Color(nsColor: $0).opacity(style.opacity) } ?? .clear)
+            .overlay {
+                RoundedRectangle(cornerRadius: 6)
+                    .strokeBorder(
+                        activeBorderColor(for: style),
+                        lineWidth: activeBorderLineWidth(for: style)
+                    )
+            }
+            .overlay(alignment: .leading) {
+                if showsLeadingRail(for: workspaceSnapshot) {
+                    Capsule(style: .continuous)
+                        .fill(railColor)
+                        .frame(width: 3)
+                        .padding(.leading, 4)
+                        .padding(.vertical, 5)
+                        .offset(x: -1)
+                }
+            }
+    }
+
     private func backgroundStyle(
-        for workspaceSnapshot: SidebarWorkspaceSnapshotBuilder.Snapshot
+        for workspaceSnapshot: SidebarWorkspaceSnapshotBuilder.Snapshot,
+        isEmphasized: Bool
     ) -> SidebarWorkspaceRowBackgroundStyle {
         sidebarWorkspaceRowBackgroundStyle(
             activeTabIndicatorStyle: activeTabIndicatorStyle,
@@ -16730,7 +16767,7 @@ struct TabItemView: View, Equatable {
             colorScheme: colorScheme,
             sidebarSelectionColorHex: sidebarSelectionColorHex,
             subtleSelection: settings.subtleSelection,
-            isEmphasized: controlActiveState != .inactive,
+            isEmphasized: isEmphasized,
             increaseContrast: colorSchemeContrast == .increased,
             accent: settings.accentColor
         )

Sources/Sidebar/AppKitList/Cells/SidebarGroupHeaderRowModel.swift

@@ -20,6 +20,9 @@ struct SidebarGroupHeaderRowModel: Equatable, Hashable {
     let isAnchorActive: Bool
     let isMultiSelected: Bool
     let multiSelectionBackgroundStyle: SidebarWorkspaceRowBackgroundStyle
+    /// Hairline painted while this header is anchor-active; nil when subtle
+    /// selection is off.
+    var anchorActiveEdgeColor: NSColor? = nil
     let memberCount: Int
     var anchorUnreadCount: Int
     var canMarkRead: Bool

Sources/Sidebar/AppKitList/Cells/SidebarGroupHeaderRowView.swift

@@ -12,7 +12,8 @@ import SwiftUI
 final class SidebarGroupHeaderTableCellView: NSTableCellView {
     static let reuseIdentifier = NSUserInterfaceItemIdentifier("SidebarGroupHeaderTableCellView")
 
-    private let backgroundView = NSView()
+    /// Selection fill and edge layer. Internal so tests read its paint directly.
+    let backgroundView = NSView()
     private let pinImageView = NSImageView()
     private let chevronButton = SidebarHeaderGlyphButton()
     private let iconImageView = NSImageView()
@@ -225,6 +226,7 @@ final class SidebarGroupHeaderTableCellView: NSTableCellView {
             ? 6
             : 4
         backgroundView.layer?.backgroundColor = headerBackgroundColor(for: model).cgColor
+        applySelectionEdge(headerSelectionEdgeColor(for: model))
 
         topDropIndicator.accentColor = model.accentColor
         bottomDropIndicator.accentColor = model.accentColor
@@ -290,6 +292,7 @@ final class SidebarGroupHeaderTableCellView: NSTableCellView {
         CATransaction.setDisableActions(true)
         backgroundView.layer?.cornerRadius = 4
         backgroundView.layer?.backgroundColor = labelColor.withAlphaComponent(0.08).cgColor
+        applySelectionEdge(model.anchorActiveEdgeColor)
         CATransaction.commit()
         nameField.textColor = labelColor
     }
@@ -302,6 +305,7 @@ final class SidebarGroupHeaderTableCellView: NSTableCellView {
         CATransaction.setDisableActions(true)
         backgroundView.layer?.cornerRadius = 6
         backgroundView.layer?.backgroundColor = headerMultiSelectionBackgroundColor(for: model).cgColor
+        applySelectionEdge(model.multiSelectionBackgroundStyle.edgeColor)
         CATransaction.commit()
     }
 
@@ -313,6 +317,7 @@ final class SidebarGroupHeaderTableCellView: NSTableCellView {
         CATransaction.setDisableActions(true)
         backgroundView.layer?.cornerRadius = 4
         backgroundView.layer?.backgroundColor = NSColor.clear.cgColor
+        applySelectionEdge(nil)
         CATransaction.commit()
         let colorScheme: ColorScheme = model.colorSchemeIsDark ? .dark : .light
         nameField.textColor = SidebarAppearanceColorResolver().resolvedColor(
@@ -348,6 +353,18 @@ final class SidebarGroupHeaderTableCellView: NSTableCellView {
         return .clear
     }
 
+    /// Subtle-selection hairline, matching selected workspace rows.
+    private func headerSelectionEdgeColor(for model: SidebarGroupHeaderRowModel) -> NSColor? {
+        if model.isAnchorActive { return model.anchorActiveEdgeColor }
+        if model.isMultiSelected { return model.multiSelectionBackgroundStyle.edgeColor }
+        return nil
+    }
+
+    private func applySelectionEdge(_ edgeColor: NSColor?) {
+        backgroundView.layer?.borderWidth = edgeColor == nil ? 0 : 1
+        backgroundView.layer?.borderColor = edgeColor?.cgColor
+    }
+
     private func headerMultiSelectionBackgroundColor(
         for model: SidebarGroupHeaderRowModel
     ) -> NSColor {

Sources/Sidebar/AppKitList/Cells/SidebarWorkspaceRowCellView.swift

@@ -249,9 +249,11 @@ final class SidebarWorkspaceRowTableCellView: NSTableCellView {
         // Only the subtle left-rail treatment depends on window activation and
         // Increase Contrast; the default solid fill never changes here.
         let settings = painted.settings
-        guard settings.subtleSelection,
-              settings.activeTabIndicatorStyle != .solidFill,
-              settings.selectionColorHex.flatMap({ NSColor(hex: $0) }) == nil else { return }
+        guard sidebarUsesSubtleSelection(
+            activeTabIndicatorStyle: settings.activeTabIndicatorStyle,
+            subtleSelection: settings.subtleSelection,
+            sidebarSelectionColorHex: settings.selectionColorHex
+        ) else { return }
         // Selection-derived foregrounds must resolve from the same window and
         // accessibility state as the fill. These notifications are rare, so
         // repaint the row from its existing model instead of leaving text

Sources/Sidebar/SidebarAppearanceSupport.swift

@@ -353,6 +353,42 @@ func sidebarSelectedWorkspaceForegroundNSColor(
     return cmuxReadableForegroundNSColor(on: backgroundColor, opacity: clampedOpacity)
 }
 
+/// Whether selected rows paint the subtle tint and hairline. Only the
+/// left-rail indicator style uses it, and a configured selection color is an
+/// explicit request for a solid fill.
+func sidebarUsesSubtleSelection(
+    activeTabIndicatorStyle: WorkspaceIndicatorStyle,
+    subtleSelection: Bool,
+    sidebarSelectionColorHex: String?
+) -> Bool {
+    subtleSelection
+        && activeTabIndicatorStyle == .leftRail
+        && sidebarSelectionColorHex.flatMap { NSColor(hex: $0) } == nil
+}
+
+/// Hairline for a group header whose anchor workspace is selected, so group
+/// headers carry the same edge as selected workspace rows in subtle-selection
+/// mode. The header keeps its neutral wash, so the edge is the neutral
+/// selection edge. Nil when subtle selection is off.
+func sidebarGroupHeaderAnchorActiveEdgeNSColor(
+    activeTabIndicatorStyle: WorkspaceIndicatorStyle,
+    subtleSelection: Bool,
+    sidebarSelectionColorHex: String?,
+    colorScheme: ColorScheme,
+    increaseContrast: Bool
+) -> NSColor? {
+    guard sidebarUsesSubtleSelection(
+        activeTabIndicatorStyle: activeTabIndicatorStyle,
+        subtleSelection: subtleSelection,
+        sidebarSelectionColorHex: sidebarSelectionColorHex
+    ) else { return nil }
+    return CmuxSelectionFill.resolve(
+        colorScheme: colorScheme,
+        isEmphasized: false,
+        increaseContrast: increaseContrast
+    ).edgeColor
+}
+
 struct SidebarWorkspaceRowBackgroundStyle: Equatable, Hashable {
     let color: NSColor?
     let opacity: Double
@@ -402,9 +438,11 @@ func sidebarWorkspaceRowBackgroundStyle(
         accent: accent
     )
     let accentBackground = accent.nsColor(for: colorScheme)
-    // A configured selection color is an explicit request for a solid fill.
-    let usesSubtleSelection = subtleSelection
-        && sidebarSelectionColorHex.flatMap { NSColor(hex: $0) } == nil
+    let usesSubtleSelection = sidebarUsesSubtleSelection(
+        activeTabIndicatorStyle: activeTabIndicatorStyle,
+        subtleSelection: subtleSelection,
+        sidebarSelectionColorHex: sidebarSelectionColorHex
+    )
     func calmFill(isSecondary: Bool) -> SidebarWorkspaceRowBackgroundStyle {
         let fill = CmuxSelectionFill.resolve(
             colorScheme: colorScheme,
@@ -465,3 +503,21 @@ extension WorkspaceIndicatorStyle {
         isActive && (self == .solidFill || increaseContrast)
     }
 }
+
+/// Reads window activation for the subtle selection wash, which dims to
+/// neutral when the window is inactive the way Finder's selection does.
+/// Rows wrap only their selection background in this reader, and only while
+/// the subtle selection paints them, so activation changes invalidate that
+/// background instead of every sidebar row.
+struct SidebarSelectionWindowActivationReader<Content: View>: View {
+    @Environment(\.controlActiveState) private var controlActiveState
+    let content: (_ isEmphasized: Bool) -> Content
+
+    init(@ViewBuilder content: @escaping (_ isEmphasized: Bool) -> Content) {
+        self.content = content
+    }
+
+    var body: some View {
+        content(controlActiveState != .inactive)
+    }
+}

Sources/SidebarWorkspaceGroupHeaderView.swift

@@ -21,6 +21,7 @@ struct SidebarWorkspaceGroupHeaderView: View, Equatable {
             lhs.isAnchorActive == rhs.isAnchorActive &&
             lhs.isMultiSelected == rhs.isMultiSelected &&
             lhs.multiSelectionBackgroundStyle == rhs.multiSelectionBackgroundStyle &&
+            lhs.anchorActiveEdgeColor == rhs.anchorActiveEdgeColor &&
             lhs.memberCount == rhs.memberCount &&
             lhs.anchorUnreadCount == rhs.anchorUnreadCount &&
             lhs.canMarkRead == rhs.canMarkRead &&
@@ -55,6 +56,9 @@ struct SidebarWorkspaceGroupHeaderView: View, Equatable {
     let isAnchorActive: Bool
     let isMultiSelected: Bool
     let multiSelectionBackgroundStyle: SidebarWorkspaceRowBackgroundStyle
+    /// Hairline painted while this header is anchor-active; nil when subtle
+    /// selection is off.
+    var anchorActiveEdgeColor: NSColor? = nil
     let memberCount: Int
     let anchorUnreadCount: Int
     let canMarkRead: Bool
@@ -127,6 +131,17 @@ struct SidebarWorkspaceGroupHeaderView: View, Equatable {
         return Color(nsColor: color).opacity(multiSelectionBackgroundStyle.opacity)
     }
 
+    /// Subtle-selection hairline, matching selected workspace rows.
+    private var selectionEdgeColor: NSColor? {
+        if isAnchorActive { return anchorActiveEdgeColor }
+        if isMultiSelected { return multiSelectionBackgroundStyle.edgeColor }
+        return nil
+    }
+
+    private var selectionCornerRadius: CGFloat {
+        isMultiSelected && !isAnchorActive ? 6 : 4
+    }
+
     var body: some View {
 #if DEBUG
         let _ = { sidebarLazyContractProbe.groupHeaderRowBody?() }()
@@ -280,9 +295,15 @@ struct SidebarWorkspaceGroupHeaderView: View, Equatable {
                     : Color.clear
         )
         .clipShape(RoundedRectangle(
-            cornerRadius: isMultiSelected && !isAnchorActive ? 6 : 4,
+            cornerRadius: selectionCornerRadius,
             style: .continuous
         ))
+        .overlay {
+            if let selectionEdgeColor {
+                RoundedRectangle(cornerRadius: selectionCornerRadius, style: .continuous)
+                    .strokeBorder(Color(nsColor: selectionEdgeColor), lineWidth: 1)
+            }
+        }
         .sidebarShortcutHintOverlay(
             text: shortcutHintPillText,
             emphasis: isAnchorActive ? 1.0 : 0.9,

Sources/SidebarWorkspaceGroupRowSnapshot.swift

@@ -18,6 +18,9 @@ struct SidebarWorkspaceGroupRowSnapshot {
     let isAnchorActive: Bool
     let isMultiSelected: Bool
     let multiSelectionBackgroundStyle: SidebarWorkspaceRowBackgroundStyle
+    /// Hairline painted while this header is anchor-active; nil when subtle
+    /// selection is off.
+    var anchorActiveEdgeColor: NSColor? = nil
     let memberCount: Int
     let anchorUnreadCount: Int
     let canMarkRead: Bool