fix: ensure terminal windows don't part from parent window when toggling visibility (#4789)

As of version 1.0.1 (macOS build) when running the toggle visibility
action a window with tabs is made into multiple windows.

This PR ensures terminal tabs are reconstructed and correctly placed
into its parent window.

# Demo


https://github.com/user-attachments/assets/44f14bca-15a1-4717-ba0a-44f0767feec3


FYI: I will create another PR to ensure the right tab is focused after
the main window is restored.

Solves #4329

macos/Ghostty.xcodeproj/project.pbxproj

@@ -72,6 +72,7 @@
 		A5A6F72A2CC41B8900B232A5 /* Xcode.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5A6F7292CC41B8700B232A5 /* Xcode.swift */; };
 		A5B30539299BEAAB0047F10C /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = A5B30538299BEAAB0047F10C /* Assets.xcassets */; };
 		A5CA378C2D2A4DEB00931030 /* KeyboardLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5CA378B2D2A4DE800931030 /* KeyboardLayout.swift */; };
+		A5CA378E2D31D6C300931030 /* Weak.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5CA378D2D31D6C100931030 /* Weak.swift */; };
 		A5CBD0562C9E65B80017A1AE /* DraggableWindowView.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5CBD0552C9E65A50017A1AE /* DraggableWindowView.swift */; };
 		A5CBD0582C9F30960017A1AE /* Cursor.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5CBD0572C9F30860017A1AE /* Cursor.swift */; };
 		A5CBD0592C9F37B10017A1AE /* Backport.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5CEAFFE29C2410700646FDA /* Backport.swift */; };
@@ -167,6 +168,7 @@
 		A5B30538299BEAAB0047F10C /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		A5B3053D299BEAAB0047F10C /* Ghostty.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = Ghostty.entitlements; sourceTree = "<group>"; };
 		A5CA378B2D2A4DE800931030 /* KeyboardLayout.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = KeyboardLayout.swift; sourceTree = "<group>"; };
+		A5CA378D2D31D6C100931030 /* Weak.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Weak.swift; sourceTree = "<group>"; };
 		A5CBD0552C9E65A50017A1AE /* DraggableWindowView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DraggableWindowView.swift; sourceTree = "<group>"; };
 		A5CBD0572C9F30860017A1AE /* Cursor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Cursor.swift; sourceTree = "<group>"; };
 		A5CBD05B2CA0C5C70017A1AE /* QuickTerminal.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = QuickTerminal.xib; sourceTree = "<group>"; };
@@ -282,6 +284,7 @@
 				AEE8B3442B9AA39600260C5E /* NSPasteboard+Extension.swift */,
 				A5985CD62C320C4500C57AD3 /* String+Extension.swift */,
 				A5CC36142C9CDA03004D6760 /* View+Extension.swift */,
+				A5CA378D2D31D6C100931030 /* Weak.swift */,
 				C1F26EE72B76CBFC00404083 /* VibrantLayer.h */,
 				C1F26EE82B76CBFC00404083 /* VibrantLayer.m */,
 				A5CEAFDA29B8005900646FDA /* SplitView */,
@@ -647,6 +650,7 @@
 				A5A6F72A2CC41B8900B232A5 /* Xcode.swift in Sources */,
 				A52FFF5B2CAA54B1000C6A5B /* FullscreenMode+Extension.swift in Sources */,
 				A5333E222B5A2128008AEFF7 /* SurfaceView_AppKit.swift in Sources */,
+				A5CA378E2D31D6C300931030 /* Weak.swift in Sources */,
 				A5CDF1952AAFA19600513312 /* ConfigurationErrorsView.swift in Sources */,
 				A55B7BBC29B6FC330055DE60 /* SurfaceView.swift in Sources */,
 				A5333E1C2B5A1CE3008AEFF7 /* CrossKit.swift in Sources */,

macos/Sources/App/macOS/AppDelegate.swift

@@ -92,10 +92,8 @@ class AppDelegate: NSObject,
         return ProcessInfo.processInfo.systemUptime - applicationLaunchTime
     }
 
-    /// Tracks whether the application is currently visible. This can be gamed, i.e. if a user manually
+    /// Tracks the windows that we hid for toggleVisibility.
-    /// brings each window one by one to the front. But at worst its off by one set of toggles and this
+    private var hiddenWindows: [Weak<NSWindow>] = []
-    /// makes our logic very easy.
-    private var isVisible: Bool = true
 
     /// The observer for the app appearance.
     private var appearanceObserver: NSKeyValueObservation? = nil
@@ -219,15 +217,20 @@ class AppDelegate: NSObject,
     }
 
     func applicationDidBecomeActive(_ notification: Notification) {
-        guard !applicationHasBecomeActive else { return }
+        // If we're back then clear the hidden windows
-        applicationHasBecomeActive = true
+        self.hiddenWindows = []
 
-        // Let's launch our first window. We only do this if we have no other windows. It
+        // First launch stuff
-        // is possible to have other windows in a few scenarios:
+        if (!applicationHasBecomeActive) {
-        //   - if we're opening a URL since `application(_:openFile:)` is called before this.
+            applicationHasBecomeActive = true
-        //   - if we're restoring from persisted state
+
-        if terminalManager.windows.count == 0 && derivedConfig.initialWindow {
+            // Let's launch our first window. We only do this if we have no other windows. It
-            terminalManager.newWindow()
+            // is possible to have other windows in a few scenarios:
+            //   - if we're opening a URL since `application(_:openFile:)` is called before this.
+            //   - if we're restoring from persisted state
+            if terminalManager.windows.count == 0 && derivedConfig.initialWindow {
+                terminalManager.newWindow()
+            }
         }
     }
 
@@ -706,21 +709,23 @@ class AppDelegate: NSObject,
 
     /// Toggles visibility of all Ghosty Terminal windows. When hidden, activates Ghostty as the frontmost application
     @IBAction func toggleVisibility(_ sender: Any) {
-        // We only care about terminal windows.
+        // If we have focus, then we hide all windows.
-        for window in NSApp.windows.filter({ $0.windowController is BaseTerminalController }) {
+        if NSApp.isActive {
-            if isVisible {
+            // We need to keep track of the windows that were visible because we only
-                window.orderOut(nil)
+            // want to bring back these windows if we remove the toggle.
-            } else {
+            self.hiddenWindows = NSApp.windows.filter { $0.isVisible }.map { Weak($0) }
-                window.makeKeyAndOrderFront(nil)
+            NSApp.hide(nil)
-            }
+            return
         }
 
-        // After bringing them all to front we make sure our app is active too.
+        // If we're not active, we want to become active
-        if !isVisible {
+        NSApp.activate(ignoringOtherApps: true)
-            NSApp.activate(ignoringOtherApps: true)
-        }
 
-        isVisible.toggle()
+        // Bring all windows to the front. Note: we don't use NSApp.unhide because
+        // that will unhide ALL hidden windows. We want to only bring forward the
+        // ones that we hid.
+        self.hiddenWindows.forEach { $0.value?.orderFrontRegardless() }
+        self.hiddenWindows = []
     }
 
     private struct DerivedConfig {

macos/Sources/Helpers/Weak.swift

@@ -0,0 +1,9 @@
+/// A wrapper that holds a weak reference to an object. This lets us create native containers
+/// of weak references.
+class Weak<T: AnyObject> {
+    weak var value: T?
+
+    init(_ value: T) {
+        self.value = value
+    }
+}

src/input/Binding.zig

@@ -441,10 +441,10 @@ pub const Action = union(enum) {
     toggle_quick_terminal: void,
 
     /// Show/hide all windows. If all windows become shown, we also ensure
-    /// Ghostty is focused.
+    /// Ghostty becomes focused. When hiding all windows, focus is yielded
+    /// to the next application as determined by the OS.
     ///
-    /// This currently only works on macOS. When hiding all windows, we do
+    /// This currently only works on macOS.
-    /// not yield focus to the previous application.
     toggle_visibility: void,
 
     /// Quit ghostty.