Right sidebar overhaul: host focus input and trailing tab bar inset

Sources/Bonsplit/Internal/Models/SplitNode.swift

@@ -42,6 +42,25 @@ indirect enum SplitNode: Identifiable, Equatable {
         }
     }
 
+    /// The pane whose tab bar ends at the tree's top-trailing corner.
+    ///
+    /// Side-by-side splits take their trailing child and stacked splits their
+    /// top child, so the result's tab bar always touches the container's top
+    /// and trailing edges.
+    var topTrailingPaneId: PaneID {
+        switch self {
+        case .pane(let state):
+            return state.id
+        case .split(let state):
+            switch state.orientation {
+            case .horizontal:
+                return state.second.topTrailingPaneId
+            case .vertical:
+                return state.first.topTrailingPaneId
+            }
+        }
+    }
+
     /// Get all pane IDs in the tree
     var allPaneIds: [PaneID] {
         switch self {

Sources/Bonsplit/Internal/Views/PaneContainerView.swift

@@ -153,6 +153,7 @@ struct PaneContainerView<Content: View, EmptyContent: View>: View {
     @Bindable var controller: SplitViewController
     let contentBuilder: (TabItem, PaneID) -> Content
     let emptyPaneBuilder: (PaneID) -> EmptyContent
+    var isMainContentFocused: Bool = true
     var showSplitButtons: Bool = true
     var tabBarVisibility: TabBarVisibility = .always
     var contentViewLifecycle: ContentViewLifecycle = .recreateOnSwitch
@@ -161,7 +162,7 @@ struct PaneContainerView<Content: View, EmptyContent: View>: View {
     @State private var dropLifecycle: PaneDropLifecycle = .idle
 
     private var isFocused: Bool {
-        controller.focusedPaneId == pane.id
+        isMainContentFocused && controller.focusedPaneId == pane.id
     }
 
     private var isTabDragActive: Bool {

Sources/Bonsplit/Internal/Views/SplitContainerView.swift

@@ -207,6 +207,7 @@ struct SplitContainerView<Content: View, EmptyContent: View>: NSViewRepresentabl
     let dividerPositionRange: ClosedRange<CGFloat>
     let contentBuilder: (TabItem, PaneID) -> Content
     let emptyPaneBuilder: (PaneID) -> EmptyContent
+    var isMainContentFocused: Bool = true
     var showSplitButtons: Bool = true
     var tabBarVisibility: TabBarVisibility = .always
     var contentViewLifecycle: ContentViewLifecycle = .recreateOnSwitch
@@ -681,6 +682,7 @@ struct SplitContainerView<Content: View, EmptyContent: View>: NSViewRepresentabl
                 controller: controller,
                 contentBuilder: contentBuilder,
                 emptyPaneBuilder: emptyPaneBuilder,
+                isMainContentFocused: isMainContentFocused,
                 showSplitButtons: showSplitButtons,
                 tabBarVisibility: tabBarVisibility,
                 contentViewLifecycle: contentViewLifecycle
@@ -693,6 +695,7 @@ struct SplitContainerView<Content: View, EmptyContent: View>: NSViewRepresentabl
                 dividerPositionRange: dividerPositionRange,
                 contentBuilder: contentBuilder,
                 emptyPaneBuilder: emptyPaneBuilder,
+                isMainContentFocused: isMainContentFocused,
                 showSplitButtons: showSplitButtons,
                 tabBarVisibility: tabBarVisibility,
                 contentViewLifecycle: contentViewLifecycle,

Sources/Bonsplit/Internal/Views/SplitNodeView.swift

@@ -11,6 +11,7 @@ struct SplitNodeView<Content: View, EmptyContent: View>: View {
     let appearance: BonsplitConfiguration.Appearance
     let dividerPositionRange: ClosedRange<CGFloat>
     var showSplitButtons: Bool = true
+    var isMainContentFocused: Bool = true
     var tabBarVisibility: TabBarVisibility = .always
     var contentViewLifecycle: ContentViewLifecycle = .recreateOnSwitch
     var onGeometryChange: ((_ isDragging: Bool) -> Void)?
@@ -25,6 +26,7 @@ struct SplitNodeView<Content: View, EmptyContent: View>: View {
                 pane: paneState,
                 contentBuilder: contentBuilder,
                 emptyPaneBuilder: emptyPaneBuilder,
+                isMainContentFocused: isMainContentFocused,
                 showSplitButtons: showSplitButtons,
                 tabBarVisibility: tabBarVisibility,
                 contentViewLifecycle: contentViewLifecycle
@@ -38,6 +40,7 @@ struct SplitNodeView<Content: View, EmptyContent: View>: View {
                 dividerPositionRange: dividerPositionRange,
                 contentBuilder: contentBuilder,
                 emptyPaneBuilder: emptyPaneBuilder,
+                isMainContentFocused: isMainContentFocused,
                 showSplitButtons: showSplitButtons,
                 tabBarVisibility: tabBarVisibility,
                 contentViewLifecycle: contentViewLifecycle,
@@ -98,6 +101,7 @@ struct SinglePaneWrapper<Content: View, EmptyContent: View>: NSViewRepresentable
     let pane: PaneState
     let contentBuilder: (TabItem, PaneID) -> Content
     let emptyPaneBuilder: (PaneID) -> EmptyContent
+    var isMainContentFocused: Bool = true
     var showSplitButtons: Bool = true
     var tabBarVisibility: TabBarVisibility = .always
     var contentViewLifecycle: ContentViewLifecycle = .recreateOnSwitch
@@ -108,6 +112,7 @@ struct SinglePaneWrapper<Content: View, EmptyContent: View>: NSViewRepresentable
             controller: controller,
             contentBuilder: contentBuilder,
             emptyPaneBuilder: emptyPaneBuilder,
+            isMainContentFocused: isMainContentFocused,
             showSplitButtons: showSplitButtons,
             tabBarVisibility: tabBarVisibility,
             contentViewLifecycle: contentViewLifecycle
@@ -165,6 +170,7 @@ struct SinglePaneWrapper<Content: View, EmptyContent: View>: NSViewRepresentable
             controller: controller,
             contentBuilder: contentBuilder,
             emptyPaneBuilder: emptyPaneBuilder,
+            isMainContentFocused: isMainContentFocused,
             showSplitButtons: showSplitButtons,
             tabBarVisibility: tabBarVisibility,
             contentViewLifecycle: contentViewLifecycle

Sources/Bonsplit/Internal/Views/SplitViewContainer.swift

@@ -8,6 +8,7 @@ struct SplitViewContainer<Content: View, EmptyContent: View>: View {
     let emptyPaneBuilder: (PaneID) -> EmptyContent
     let appearance: BonsplitConfiguration.Appearance
     let dividerPositionRange: ClosedRange<CGFloat>
+    var isMainContentFocused: Bool = true
     var showSplitButtons: Bool = true
     var tabBarVisibility: TabBarVisibility = .always
     var contentViewLifecycle: ContentViewLifecycle = .recreateOnSwitch
@@ -48,6 +49,7 @@ struct SplitViewContainer<Content: View, EmptyContent: View>: View {
             appearance: appearance,
             dividerPositionRange: dividerPositionRange,
             showSplitButtons: showSplitButtons,
+            isMainContentFocused: isMainContentFocused,
             tabBarVisibility: tabBarVisibility,
             contentViewLifecycle: contentViewLifecycle,
             onGeometryChange: onGeometryChange,

Sources/Bonsplit/Internal/Views/TabBarView.swift

@@ -1172,7 +1172,38 @@ struct TabBarView: View {
         .frame(height: tabBarHeight, alignment: .topLeading)
     }
 
+    /// Width reserved after this tab bar's action lane for a host-owned control.
+    /// Only the pane at the container's top-trailing corner reserves it.
+    private var reservedTrailingInset: CGFloat {
+        let inset = appearance.tabBarTrailingInset
+        guard inset > 0 else { return 0 }
+        let cornerPaneId = splitViewController.zoomedPaneId
+            ?? controller.internalController.rootNode.topTrailingPaneId
+        return cornerPaneId == pane.id ? inset : 0
+    }
+
     var body: some View {
+        let trailingInset = reservedTrailingInset
+        tabBarContent
+            .padding(.trailing, trailingInset)
+            .background(alignment: .trailing) {
+                if trailingInset > 0 {
+                    TabBarDragZoneView(
+                        isMinimalMode: isMinimalMode,
+                        isFocusedPane: isFocused,
+                        onSingleClick: focusPaneFromTabBarChrome
+                    ) { return false }
+                        .frame(width: trailingInset, height: tabBarHeight)
+                        .background(
+                            TabBarLayerBackedColor(color: chromeSnapshot.barColor)
+                                .frame(width: trailingInset, height: tabBarHeight)
+                        )
+                        .accessibilityIdentifier("paneTabBar.trailingInset")
+                }
+            }
+    }
+
+    private var tabBarContent: some View {
         HStack(spacing: 0) {
             if appearance.tabBarLeadingInset > 0 && controller.internalController.rootNode.allPaneIds.first == pane.id {
                 TabBarDragZoneView(

Sources/Bonsplit/Public/BonsplitConfiguration.swift

@@ -595,6 +595,11 @@ extension BonsplitConfiguration {
         /// Extra leading inset for the tab bar (e.g. for traffic light buttons when sidebar is collapsed)
         public var tabBarLeadingInset: CGFloat
 
+        /// Extra trailing inset reserved at the end of the top-trailing pane's tab bar,
+        /// after its action buttons, for a host-owned control drawn over that corner.
+        /// A zoomed pane receives the inset because it fills the container.
+        public var tabBarTrailingInset: CGFloat
+
         /// Tooltip text for the tab bar's right-side action buttons
         public var splitButtonTooltips: SplitButtonTooltips
 
@@ -654,6 +659,7 @@ extension BonsplitConfiguration {
             splitButtonBackdropStyle: SplitButtonBackdropStyle? = nil,
             splitButtonBackdropEffect: SplitButtonBackdropEffect? = nil,
             tabBarLeadingInset: CGFloat = 0,
+            tabBarTrailingInset: CGFloat = 0,
             splitButtonTooltips: SplitButtonTooltips = .default,
             animationDuration: Double = 0.15,
             enableAnimations: Bool = true,
@@ -676,6 +682,7 @@ extension BonsplitConfiguration {
             self.splitButtonBackdropStyle = splitButtonBackdropStyle
             self.splitButtonBackdropEffect = splitButtonBackdropEffect
             self.tabBarLeadingInset = tabBarLeadingInset
+            self.tabBarTrailingInset = tabBarTrailingInset
             self.splitButtonTooltips = splitButtonTooltips
             self.animationDuration = animationDuration
             self.enableAnimations = enableAnimations

Sources/Bonsplit/Public/BonsplitView.swift

@@ -19,6 +19,10 @@ import SwiftUI
 /// ```
 public struct BonsplitView<Content: View, EmptyContent: View>: View {
     @Bindable private var controller: BonsplitController
+    /// Whether the main pane currently owns keyboard focus. Selection remains
+    /// owned by Bonsplit, but a host may move focus to an adjacent surface
+    /// while keeping the selected pane alive.
+    private let isMainContentFocused: Bool
     private let contentBuilder: (Tab, PaneID) -> Content
     private let emptyPaneBuilder: (PaneID) -> EmptyContent
 
@@ -29,10 +33,12 @@ public struct BonsplitView<Content: View, EmptyContent: View>: View {
     ///   - emptyPane: A ViewBuilder closure that provides content for empty panes
     public init(
         controller: BonsplitController,
+        isMainContentFocused: Bool = true,
         @ViewBuilder content: @escaping (Tab, PaneID) -> Content,
         @ViewBuilder emptyPane: @escaping (PaneID) -> EmptyContent
     ) {
         self.controller = controller
+        self.isMainContentFocused = isMainContentFocused
         self.contentBuilder = content
         self.emptyPaneBuilder = emptyPane
     }
@@ -47,6 +53,7 @@ public struct BonsplitView<Content: View, EmptyContent: View>: View {
             },
             appearance: controller.configuration.appearance,
             dividerPositionRange: controller.configuration.dividerPositionRange,
+            isMainContentFocused: isMainContentFocused,
             showSplitButtons: controller.configuration.allowSplits && controller.configuration.appearance.showSplitButtons,
             tabBarVisibility: controller.configuration.tabBarVisibility,
             contentViewLifecycle: controller.configuration.contentViewLifecycle,
@@ -70,9 +77,11 @@ extension BonsplitView where EmptyContent == DefaultEmptyPaneView {
     ///   - content: A ViewBuilder closure that provides content for each tab. Receives the tab and pane ID.
     public init(
         controller: BonsplitController,
+        isMainContentFocused: Bool = true,
         @ViewBuilder content: @escaping (Tab, PaneID) -> Content
     ) {
         self.controller = controller
+        self.isMainContentFocused = isMainContentFocused
         self.contentBuilder = content
         self.emptyPaneBuilder = { _ in DefaultEmptyPaneView() }
     }

Tests/BonsplitTests/TopTrailingPaneTests.swift

@@ -0,0 +1,34 @@
+import XCTest
+@testable import Bonsplit
+
+/// The top-trailing pane owns the host's reserved tab-bar trailing inset.
+@MainActor
+final class TopTrailingPaneTests: XCTestCase {
+    func testSinglePaneIsTopTrailing() throws {
+        let controller = BonsplitController()
+        let pane = try XCTUnwrap(controller.allPaneIds.first)
+        XCTAssertEqual(controller.internalController.rootNode.topTrailingPaneId, pane)
+    }
+
+    func testSideBySideSplitUsesTrailingPane() throws {
+        let controller = BonsplitController()
+        let leading = try XCTUnwrap(controller.allPaneIds.first)
+        let trailing = try XCTUnwrap(controller.splitPane(leading, orientation: .horizontal))
+        XCTAssertEqual(controller.internalController.rootNode.topTrailingPaneId, trailing)
+    }
+
+    func testStackedSplitUsesTopPane() throws {
+        let controller = BonsplitController()
+        let top = try XCTUnwrap(controller.allPaneIds.first)
+        _ = try XCTUnwrap(controller.splitPane(top, orientation: .vertical))
+        XCTAssertEqual(controller.internalController.rootNode.topTrailingPaneId, top)
+    }
+
+    func testNestedSplitUsesTopOfTrailingColumn() throws {
+        let controller = BonsplitController()
+        let leading = try XCTUnwrap(controller.allPaneIds.first)
+        let trailingTop = try XCTUnwrap(controller.splitPane(leading, orientation: .horizontal))
+        _ = try XCTUnwrap(controller.splitPane(trailingTop, orientation: .vertical))
+        XCTAssertEqual(controller.internalController.rootNode.topTrailingPaneId, trailingTop)
+    }
+}