Update app and tooling

Sources/Backport.swift

@@ -0,0 +1,59 @@
+import SwiftUI
+
+// Centralized backports for newer SwiftUI APIs we want to use when available.
+struct Backport<Content> {
+    let content: Content
+}
+
+extension View {
+    var backport: Backport<Self> { Backport(content: self) }
+}
+
+extension Backport where Content: View {
+    func pointerStyle(_ style: BackportPointerStyle?) -> some View {
+        #if canImport(AppKit)
+        if #available(macOS 15, *) {
+            return content.pointerStyle(style?.official)
+        } else {
+            return content
+        }
+        #else
+        return content
+        #endif
+    }
+}
+
+enum BackportPointerStyle {
+    case `default`
+    case grabIdle
+    case grabActive
+    case horizontalText
+    case verticalText
+    case link
+    case resizeLeft
+    case resizeRight
+    case resizeUp
+    case resizeDown
+    case resizeUpDown
+    case resizeLeftRight
+
+    #if canImport(AppKit)
+    @available(macOS 15, *)
+    var official: PointerStyle {
+        switch self {
+        case .default: return .default
+        case .grabIdle: return .grabIdle
+        case .grabActive: return .grabActive
+        case .horizontalText: return .horizontalText
+        case .verticalText: return .verticalText
+        case .link: return .link
+        case .resizeLeft: return .frameResize(position: .trailing, directions: [.inward])
+        case .resizeRight: return .frameResize(position: .leading, directions: [.inward])
+        case .resizeUp: return .frameResize(position: .bottom, directions: [.inward])
+        case .resizeDown: return .frameResize(position: .top, directions: [.inward])
+        case .resizeUpDown: return .frameResize(position: .top)
+        case .resizeLeftRight: return .frameResize(position: .trailing)
+        }
+    }
+    #endif
+}

Sources/Splits/SplitView.swift

@@ -1,3 +1,4 @@
+import AppKit
 import SwiftUI
 
 /// A split view shows a left and right (or top and bottom) view with a divider in the middle to do resizing.
@@ -141,6 +142,16 @@ private struct Divider: View {
     let invisibleSize: CGFloat
     let color: Color
     @Binding var split: CGFloat
+    @State private var isHovering = false
+
+    private var pointerStyle: BackportPointerStyle {
+        switch direction {
+        case .horizontal:
+            return .resizeLeftRight
+        case .vertical:
+            return .resizeUpDown
+        }
+    }
 
     var body: some View {
         ZStack {
@@ -155,6 +166,33 @@ private struct Divider: View {
         }
         .frame(width: direction == .horizontal ? invisibleSize : nil,
                height: direction == .vertical ? invisibleSize : nil)
+        .contentShape(Rectangle())
+        .backport.pointerStyle(pointerStyle)
+        .onHover { hovering in
+            if #available(macOS 15, *) {
+                return
+            }
+            guard hovering != isHovering else { return }
+            isHovering = hovering
+            if hovering {
+                switch direction {
+                case .horizontal:
+                    NSCursor.resizeLeftRight.push()
+                case .vertical:
+                    NSCursor.resizeUpDown.push()
+                }
+            } else {
+                NSCursor.pop()
+            }
+        }
+        .onDisappear {
+            if #available(macOS 15, *) {
+                return
+            }
+            guard isHovering else { return }
+            isHovering = false
+            NSCursor.pop()
+        }
     }
 }
 

Sources/WindowDecorationsController.swift

@@ -42,10 +42,10 @@ final class WindowDecorationsController {
         if window.isSheet {
             return true
         }
-        if window is NSPanel {
+        if window.styleMask.contains(.docModalWindow) {
             return true
         }
-        if window.styleMask.contains(.utilityWindow) || window.styleMask.contains(.docModalWindow) {
+        if window.styleMask.contains(.nonactivatingPanel) {
             return true
         }
         return false