Fix instant switching window order

Reef/Models/CyclePanelState.swift

@@ -118,6 +118,23 @@ final class CyclePanelState: ObservableObject {
         return (focusedIndex + 1) % windowIDs.count
     }
 
+    nonisolated static func reconciledWindowIDs(
+        previousWindowIDs: [CGWindowID],
+        availableWindowIDs: [CGWindowID]
+    ) -> [CGWindowID] {
+        let availableWindowIDSet = Set(availableWindowIDs)
+        var includedWindowIDs = Set<CGWindowID>()
+
+        let existingWindowIDs = previousWindowIDs.filter {
+            availableWindowIDSet.contains($0) && includedWindowIDs.insert($0).inserted
+        }
+        let newWindowIDs = availableWindowIDs.filter {
+            includedWindowIDs.insert($0).inserted
+        }
+
+        return existingWindowIDs + newWindowIDs
+    }
+
     func removeCurrentItem() {
         guard items.indices.contains(selectedIndex) else { return }
 

Reef/UI/CyclePanel/CyclePanelController.swift

@@ -17,6 +17,8 @@ final class CyclePanelController: NSObject {
     private var keyDownMonitor: Any?
     private var currentApplication: Application?
     private var panelAnchorCenter: CGPoint?
+    private var directCycleApplication: Application?
+    private var directCycleWindowIDs: [CGWindowID] = []
 
     private let panelContentWidth: CGFloat = 400
     private let maxPanelFrameHeightCap: CGFloat = 520
@@ -158,15 +160,39 @@ final class CyclePanelController: NSObject {
             return frontApplication.getFocusedWindow()?.cgWindowID
         }()
 
-        let windowIDs = windows.map(\.cgWindowID)
+        let availableWindowIDs = windows.compactMap(\.cgWindowID)
+        guard availableWindowIDs.count == windows.count else {
+            let windowIDs = windows.map(\.cgWindowID)
+            guard let index = CyclePanelState.nextWindowIndex(
+                windowIDs: windowIDs,
+                focusedWindowID: focusedWindowID
+            ) else {
+                return
+            }
+
+            windows[index].focus()
+            return
+        }
+
+        if directCycleApplication.map({ isSameApplication($0, application) }) != true {
+            directCycleApplication = application
+            directCycleWindowIDs = []
+        }
+
+        directCycleWindowIDs = CyclePanelState.reconciledWindowIDs(
+            previousWindowIDs: directCycleWindowIDs,
+            availableWindowIDs: availableWindowIDs
+        )
+
         guard let index = CyclePanelState.nextWindowIndex(
-            windowIDs: windowIDs,
+            windowIDs: directCycleWindowIDs.map(Optional.some),
             focusedWindowID: focusedWindowID
         ) else {
             return
         }
 
-        windows[index].focus()
+        let nextWindowID = directCycleWindowIDs[index]
+        windows.first { $0.cgWindowID == nextWindowID }?.focus()
     }
 
     func isShowingSwitcher(for application: Application) -> Bool {

ReefTests/InstantSwitchModeTests.swift

@@ -60,4 +60,23 @@ struct InstantSwitchModeTests {
 
         #expect(index == 0)
     }
+
+    @Test func directSwitchKeepsStableOrderWhenFocusedWindowMovesToFront() {
+        let initialOrder = CyclePanelState.reconciledWindowIDs(
+            previousWindowIDs: [],
+            availableWindowIDs: [10, 20, 30]
+        )
+        let reorderedWindows = CyclePanelState.reconciledWindowIDs(
+            previousWindowIDs: initialOrder,
+            availableWindowIDs: [20, 10, 30]
+        )
+        let nextIndex = CyclePanelState.nextWindowIndex(
+            windowIDs: reorderedWindows.map(Optional.some),
+            focusedWindowID: 20
+        )
+        let nextWindowID = nextIndex.map { reorderedWindows[$0] }
+
+        #expect(reorderedWindows == [10, 20, 30])
+        #expect(nextWindowID == 30)
+    }
 }