Keep Cmd-Shift-N windows on source display

Sources/AppDelegate.swift

@@ -5473,7 +5473,32 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
     }
 
     @objc func openNewMainWindow(_ sender: Any?) {
-        _ = createMainWindow()
+        _ = createMainWindow(sourceWindow: preferredSourceWindowForNewMainWindow(sender: sender))
+    }
+
+    func openNewMainWindow(preferredWindow: NSWindow?) {
+        _ = createMainWindow(sourceWindow: preferredWindow)
+    }
+
+    private func preferredSourceWindowForNewMainWindow(sender: Any?) -> NSWindow? {
+        if let window = sender as? NSWindow, isMainTerminalWindow(window) {
+            return window
+        }
+        if let event = NSApp.currentEvent,
+           let window = mainWindowForShortcutEvent(event) {
+            return window
+        }
+        if let keyWindow = NSApp.keyWindow, isMainTerminalWindow(keyWindow) {
+            return keyWindow
+        }
+        if let mainWindow = NSApp.mainWindow, isMainTerminalWindow(mainWindow) {
+            return mainWindow
+        }
+        if let context = preferredRegisteredMainWindowContext(),
+           let window = resolvedWindow(for: context) {
+            return window
+        }
+        return nil
     }
 
     func scheduleInitialMainWindowBootstrap(debugSource: String) {
@@ -6177,11 +6202,50 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         return true
     }
 
+    private func resolvedMainWindowSource(_ window: NSWindow?) -> NSWindow? {
+        guard let window else { return nil }
+        if isMainTerminalWindow(window) {
+            return window
+        }
+        if let context = contextForMainWindow(window) ?? contextForMainTerminalWindow(window) {
+            return resolvedWindow(for: context)
+        }
+        return nil
+    }
+
+    private func positionNewMainWindow(_ window: NSWindow, relativeTo sourceWindow: NSWindow) {
+        let sourceFrame = sourceWindow.frame
+        let sourceScreen = sourceWindow.screen
+            ?? NSScreen.screens.first(where: { $0.frame.intersects(sourceFrame) })
+        guard let visibleFrame = sourceScreen?.visibleFrame else {
+            window.center()
+            return
+        }
+
+        let cascadeOffset: CGFloat = 24
+        let minimumWindowSize = NSSize(width: 460, height: 360)
+        var frame = window.frame
+        frame.origin = NSPoint(
+            x: sourceFrame.minX + cascadeOffset,
+            y: sourceFrame.maxY - cascadeOffset - frame.height
+        )
+        window.setFrame(
+            Self.clampFrame(
+                frame,
+                within: visibleFrame,
+                minWidth: minimumWindowSize.width,
+                minHeight: minimumWindowSize.height
+            ),
+            display: false
+        )
+    }
+
     @discardableResult
     func createMainWindow(
         initialWorkingDirectory: String? = nil,
         sessionWindowSnapshot: SessionWindowSnapshot? = nil,
-        shouldActivate: Bool = true
+        shouldActivate: Bool = true,
+        sourceWindow preferredSourceWindow: NSWindow? = nil
     ) -> UUID {
         let windowId = UUID()
         let tabManager = TabManager(initialWorkingDirectory: initialWorkingDirectory)
@@ -6235,7 +6299,8 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         let sourceContext = preferredMainWindowContextForWorkspaceCreation(
             debugSource: "createMainWindow.initialGeometry"
         )
-        let sourceWindow = sourceContext.flatMap { resolvedWindow(for: $0) }
+        let sourceWindow = resolvedMainWindowSource(preferredSourceWindow)
+            ?? sourceContext.flatMap { resolvedWindow(for: $0) }
         let existingFrame = sourceWindow?.frame
         let sourceWindowIsNativeFullScreen: Bool = {
 #if DEBUG
@@ -6279,6 +6344,8 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         let restoredFrame = resolvedWindowFrame(from: sessionWindowSnapshot)
         if let restoredFrame {
             window.setFrame(restoredFrame, display: false)
+        } else if let sourceWindow {
+            positionNewMainWindow(window, relativeTo: sourceWindow)
         } else {
             window.center()
             // Cascade using the same algorithm as upstream Ghostty: seed from
@@ -10299,7 +10366,7 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         // after a browser panel has been shown, SwiftUI's menu dispatch can silently
         // consume the key equivalent without firing the action closure.
         if matchConfiguredShortcut(event: event, action: .newWindow) {
-            openNewMainWindow(nil)
+            openNewMainWindow(preferredWindow: mainWindowForShortcutEvent(event))
             return true
         }
 

Sources/ContentView.swift

@@ -7683,7 +7683,8 @@ struct ContentView: View {
             }
         }
         registry.register(commandId: "palette.newWindow") {
-            AppDelegate.shared?.openNewMainWindow(nil)
+            guard let appDelegate = AppDelegate.shared else { return }
+            appDelegate.openNewMainWindow(preferredWindow: appDelegate.mainWindow(for: windowId))
         }
         registry.register(commandId: "palette.installCLI") {
             AppDelegate.shared?.installCmuxCLIInPath(nil)

cmuxTests/AppDelegateShortcutRoutingTests.swift

@@ -871,6 +871,93 @@ final class AppDelegateShortcutRoutingTests: XCTestCase {
         createdWindowId = newWindowIds.first
     }
 
+    func testCmdShiftNCreatesWindowFromEventWindowWithoutAddingWorkspace() {
+        guard let appDelegate = AppDelegate.shared else {
+            XCTFail("Expected AppDelegate.shared")
+            return
+        }
+
+        let firstWindowId = appDelegate.createMainWindow()
+        let secondWindowId = appDelegate.createMainWindow()
+        var createdWindowId: UUID?
+
+        defer {
+            if let createdWindowId {
+                closeWindow(withId: createdWindowId)
+            }
+            closeWindow(withId: firstWindowId)
+            closeWindow(withId: secondWindowId)
+        }
+
+        guard let firstManager = appDelegate.tabManagerFor(windowId: firstWindowId),
+              let secondManager = appDelegate.tabManagerFor(windowId: secondWindowId),
+              let firstWindow = window(withId: firstWindowId),
+              let secondWindow = window(withId: secondWindowId),
+              let visibleFrame = (secondWindow.screen ?? NSScreen.main)?.visibleFrame else {
+            XCTFail("Expected both window contexts to exist")
+            return
+        }
+
+        let firstFrame = NSRect(
+            x: visibleFrame.minX + 40,
+            y: visibleFrame.maxY - 460,
+            width: 760,
+            height: 420
+        )
+        let secondFrame = NSRect(
+            x: min(visibleFrame.minX + 180, visibleFrame.maxX - 600),
+            y: max(visibleFrame.minY + 80, visibleFrame.maxY - 560),
+            width: 560,
+            height: 380
+        )
+        firstWindow.setFrame(firstFrame, display: true)
+        secondWindow.setFrame(secondFrame, display: true)
+        firstWindow.makeKeyAndOrderFront(nil)
+        RunLoop.main.run(until: Date(timeIntervalSinceNow: 0.05))
+
+        let eventSourceFrame = secondWindow.frame
+        let firstCount = firstManager.tabs.count
+        let secondCount = secondManager.tabs.count
+        let existingWindowIds = mainWindowIds()
+
+        guard let event = makeKeyDownEvent(
+            key: "n",
+            modifiers: [.command, .shift],
+            keyCode: 45,
+            windowNumber: secondWindow.windowNumber
+        ) else {
+            XCTFail("Failed to construct Cmd+Shift+N event")
+            return
+        }
+
+#if DEBUG
+        XCTAssertTrue(appDelegate.debugHandleCustomShortcut(event: event))
+#else
+        XCTFail("debugHandleCustomShortcut is only available in DEBUG")
+#endif
+        RunLoop.main.run(until: Date(timeIntervalSinceNow: 0.05))
+
+        let newWindowIds = mainWindowIds().subtracting(existingWindowIds)
+        XCTAssertEqual(newWindowIds.count, 1, "Cmd+Shift+N should create one new main window")
+        createdWindowId = newWindowIds.first
+
+        XCTAssertEqual(firstManager.tabs.count, firstCount, "Cmd+Shift+N must not create a workspace in the key window")
+        XCTAssertEqual(secondManager.tabs.count, secondCount, "Cmd+Shift+N must not create a workspace in the event window")
+
+        guard let createdWindowId,
+              let createdWindow = window(withId: createdWindowId) else {
+            XCTFail("Expected created window")
+            return
+        }
+
+        XCTAssertEqual(createdWindow.frame.width, eventSourceFrame.width, accuracy: 1)
+        XCTAssertEqual(createdWindow.frame.height, eventSourceFrame.height, accuracy: 1)
+        XCTAssertTrue(
+            visibleFrame.contains(createdWindow.frame),
+            "New window should be placed inside the source window display"
+        )
+    }
+
     func testAddWorkspaceInPreferredMainWindowUsesKeyWindowWhenObjectKeyLookupIsMismatched() {
         guard let appDelegate = AppDelegate.shared else {
             XCTFail("Expected AppDelegate.shared")