Fix terminal portal tab drop routing

GhosttyTabs.xcodeproj/project.pbxproj

@@ -18,6 +18,14 @@
 		36CE99ED050785B5E96B72BB /* AuthCallbackRouter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 61A19A4145F034965110CF87 /* AuthCallbackRouter.swift */; };
 		4378399A7C0245EF8186F306 /* OmnibarAndToolsTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = B09C007F42697761B5F1A2AB /* OmnibarAndToolsTests.swift */; };
 		46F6AC15863EC84DCD3770A2 /* TerminalAndGhosttyTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 02FC74F2C27127CC565B3E8C /* TerminalAndGhosttyTests.swift */; };
+		D0B10000A1B2C3D4E5F60001 /* TerminalPaneDropTargetView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B10001A1B2C3D4E5F60001 /* TerminalPaneDropTargetView.swift */; };
+		D0B10002A1B2C3D4E5F60001 /* BonsplitTabBarPassThrough.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B10003A1B2C3D4E5F60001 /* BonsplitTabBarPassThrough.swift */; };
+		D0B10004A1B2C3D4E5F60001 /* WorkspacePortalPaneDrop.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B10005A1B2C3D4E5F60001 /* WorkspacePortalPaneDrop.swift */; };
+		D0B10006A1B2C3D4E5F60001 /* TerminalWindowPortalDebug.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B10007A1B2C3D4E5F60001 /* TerminalWindowPortalDebug.swift */; };
+		D0B10008A1B2C3D4E5F60001 /* PortalTabDragRoutingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B10009A1B2C3D4E5F60001 /* PortalTabDragRoutingTests.swift */; };
+		D0B1000AA1B2C3D4E5F60001 /* GhosttyTerminalViewSupport.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B1000BA1B2C3D4E5F60001 /* GhosttyTerminalViewSupport.swift */; };
+		D0B1000CA1B2C3D4E5F60001 /* CmuxWebViewDragRoutingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B1000DA1B2C3D4E5F60001 /* CmuxWebViewDragRoutingTests.swift */; };
+		D0B1000EA1B2C3D4E5F60001 /* BrowserPaneDropRoutingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B1000FA1B2C3D4E5F60001 /* BrowserPaneDropRoutingTests.swift */; };
 		5EDB6027B346C46521A93C74 /* CMUXAuthCore in Frameworks */ = {isa = PBXBuildFile; productRef = 29813FE5A6CBC1019289A251 /* CMUXAuthCore */; };
 		AA11BB22CC33DD44EE550001 /* CMUXWorkstream in Frameworks */ = {isa = PBXBuildFile; productRef = AA11BB22CC33DD44EE550002 /* CMUXWorkstream */; };
 		FEED0000000000000000F002 /* FeedCoordinator.swift in Sources */ = {isa = PBXBuildFile; fileRef = FEED0000000000000000F001 /* FeedCoordinator.swift */; };
@@ -273,6 +281,9 @@
 
 /* Begin PBXFileReference section */
 		02FC74F2C27127CC565B3E8C /* TerminalAndGhosttyTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TerminalAndGhosttyTests.swift; sourceTree = "<group>"; };
+		D0B10009A1B2C3D4E5F60001 /* PortalTabDragRoutingTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PortalTabDragRoutingTests.swift; sourceTree = "<group>"; };
+		D0B1000DA1B2C3D4E5F60001 /* CmuxWebViewDragRoutingTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CmuxWebViewDragRoutingTests.swift; sourceTree = "<group>"; };
+		D0B1000FA1B2C3D4E5F60001 /* BrowserPaneDropRoutingTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BrowserPaneDropRoutingTests.swift; sourceTree = "<group>"; };
 		10D684CFFB8CDEF89CE2D9E1 /* TabManagerSessionSnapshotTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TabManagerSessionSnapshotTests.swift; sourceTree = "<group>"; };
 		14A7DC53B9CA33BE2A421711 /* WorkspacePullRequestSidebarTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WorkspacePullRequestSidebarTests.swift; sourceTree = "<group>"; };
 		1D301919B10F22B8708E8883 /* WorkspaceManualUnreadTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WorkspaceManualUnreadTests.swift; sourceTree = "<group>"; };
@@ -331,6 +342,8 @@
 		E30750000000000000000001 /* WorkspaceTabColorResolution.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WorkspaceTabColorResolution.swift; sourceTree = "<group>"; };
 		A5001014 /* GhosttyConfig.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GhosttyConfig.swift; sourceTree = "<group>"; };
 		A5001015 /* GhosttyTerminalView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GhosttyTerminalView.swift; sourceTree = "<group>"; };
+		D0B1000BA1B2C3D4E5F60001 /* GhosttyTerminalViewSupport.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GhosttyTerminalViewSupport.swift; sourceTree = "<group>"; };
+		D0B10001A1B2C3D4E5F60001 /* TerminalPaneDropTargetView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TerminalPaneDropTargetView.swift; sourceTree = "<group>"; };
 		A5001016 /* GhosttyKit.xcframework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcframework; path = GhosttyKit.xcframework; sourceTree = "<group>"; };
 		A5001017 /* ghostty.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ghostty.h; sourceTree = "<group>"; };
 		A5001018 /* cmux-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "cmux-Bridging-Header.h"; sourceTree = "<group>"; };
@@ -367,6 +380,7 @@
 		A5001414 /* BrowserPanelView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Panels/BrowserPanelView.swift; sourceTree = "<group>"; };
 		A5001415 /* PanelContentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Panels/PanelContentView.swift; sourceTree = "<group>"; };
 		A5001416 /* Workspace.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Workspace.swift; sourceTree = "<group>"; };
+		D0B10005A1B2C3D4E5F60001 /* WorkspacePortalPaneDrop.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WorkspacePortalPaneDrop.swift; sourceTree = "<group>"; };
 		C0DE32470000000000000004 /* WorkspaceSurfaceIdentifierClipboardText.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WorkspaceSurfaceIdentifierClipboardText.swift; sourceTree = "<group>"; };
 		A5001417 /* WorkspaceContentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WorkspaceContentView.swift; sourceTree = "<group>"; };
 		E30760000000000000000001 /* TmuxWorkspacePaneOverlayView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TmuxWorkspacePaneOverlayView.swift; sourceTree = "<group>"; };
@@ -376,7 +390,9 @@
 		A5001511 /* UITestRecorder.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UITestRecorder.swift; sourceTree = "<group>"; };
 		A5001520 /* PostHogAnalytics.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogAnalytics.swift; sourceTree = "<group>"; };
 		A5001531 /* TerminalWindowPortal.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TerminalWindowPortal.swift; sourceTree = "<group>"; };
+		D0B10007A1B2C3D4E5F60001 /* TerminalWindowPortalDebug.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TerminalWindowPortalDebug.swift; sourceTree = "<group>"; };
 		A5001533 /* BrowserWindowPortal.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BrowserWindowPortal.swift; sourceTree = "<group>"; };
+		D0B10003A1B2C3D4E5F60001 /* BonsplitTabBarPassThrough.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BonsplitTabBarPassThrough.swift; sourceTree = "<group>"; };
 		A5001541 /* PortScanner.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PortScanner.swift; sourceTree = "<group>"; };
 		A5001544 /* TerminalImageTransfer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TerminalImageTransfer.swift; sourceTree = "<group>"; };
 		A5001545 /* TerminalSSHSessionDetector.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TerminalSSHSessionDetector.swift; sourceTree = "<group>"; };
@@ -645,13 +661,18 @@
 				A5001511 /* UITestRecorder.swift */,
 				A5001520 /* PostHogAnalytics.swift */,
 				A5001416 /* Workspace.swift */,
+				D0B10005A1B2C3D4E5F60001 /* WorkspacePortalPaneDrop.swift */,
 				C0DE32470000000000000004 /* WorkspaceSurfaceIdentifierClipboardText.swift */,
 				A5001417 /* WorkspaceContentView.swift */,
 				E30760000000000000000001 /* TmuxWorkspacePaneOverlayView.swift */,
 				A5001014 /* GhosttyConfig.swift */,
 				A5001015 /* GhosttyTerminalView.swift */,
+				D0B1000BA1B2C3D4E5F60001 /* GhosttyTerminalViewSupport.swift */,
+				D0B10001A1B2C3D4E5F60001 /* TerminalPaneDropTargetView.swift */,
 				A5001531 /* TerminalWindowPortal.swift */,
+				D0B10007A1B2C3D4E5F60001 /* TerminalWindowPortalDebug.swift */,
 				A5001533 /* BrowserWindowPortal.swift */,
+				D0B10003A1B2C3D4E5F60001 /* BonsplitTabBarPassThrough.swift */,
 				A5001019 /* TerminalController.swift */,
 				A5001541 /* PortScanner.swift */,
 				A5001544 /* TerminalImageTransfer.swift */,
@@ -762,7 +783,10 @@
 				A50019B3 /* SettingsSearchIndexTests.swift */,
 				970226F3C99D0D937CD00539 /* BrowserConfigTests.swift */,
 				58C7B1B978620BE162CC057E /* BrowserPanelTests.swift */,
+				D0B1000DA1B2C3D4E5F60001 /* CmuxWebViewDragRoutingTests.swift */,
+				D0B1000FA1B2C3D4E5F60001 /* BrowserPaneDropRoutingTests.swift */,
 				02FC74F2C27127CC565B3E8C /* TerminalAndGhosttyTests.swift */,
+				D0B10009A1B2C3D4E5F60001 /* PortalTabDragRoutingTests.swift */,
 				71F8ED91A4B55D34BE6A0668 /* WorkspaceUnitTests.swift */,
 				BEE83F8394D90ACACD8E19DD /* WindowAndDragTests.swift */,
 				6083A7DAD962E287FC2FFE94 /* ShortcutAndCommandPaletteTests.swift */,
@@ -1049,13 +1073,18 @@
 				A5001501 /* UITestRecorder.swift in Sources */,
 				A5001521 /* PostHogAnalytics.swift in Sources */,
 				A5001406 /* Workspace.swift in Sources */,
+				D0B10004A1B2C3D4E5F60001 /* WorkspacePortalPaneDrop.swift in Sources */,
 				C0DE32470000000000000003 /* WorkspaceSurfaceIdentifierClipboardText.swift in Sources */,
 				A5001407 /* WorkspaceContentView.swift in Sources */,
 				E30760000000000000000002 /* TmuxWorkspacePaneOverlayView.swift in Sources */,
 				A5001004 /* GhosttyConfig.swift in Sources */,
 				A5001005 /* GhosttyTerminalView.swift in Sources */,
+				D0B1000AA1B2C3D4E5F60001 /* GhosttyTerminalViewSupport.swift in Sources */,
+				D0B10000A1B2C3D4E5F60001 /* TerminalPaneDropTargetView.swift in Sources */,
 				A5001532 /* TerminalWindowPortal.swift in Sources */,
+				D0B10006A1B2C3D4E5F60001 /* TerminalWindowPortalDebug.swift in Sources */,
 				A5001534 /* BrowserWindowPortal.swift in Sources */,
+				D0B10002A1B2C3D4E5F60001 /* BonsplitTabBarPassThrough.swift in Sources */,
 				A5001007 /* TerminalController.swift in Sources */,
 				A5001540 /* PortScanner.swift in Sources */,
 				A5001542 /* TerminalImageTransfer.swift in Sources */,
@@ -1200,7 +1229,10 @@
 				A50019B2 /* SettingsSearchIndexTests.swift in Sources */,
 				E12E88F82733EC42F32C36A3 /* BrowserConfigTests.swift in Sources */,
 				1F14445B9627DE9D3AF4FD2E /* BrowserPanelTests.swift in Sources */,
+				D0B1000CA1B2C3D4E5F60001 /* CmuxWebViewDragRoutingTests.swift in Sources */,
+				D0B1000EA1B2C3D4E5F60001 /* BrowserPaneDropRoutingTests.swift in Sources */,
 				46F6AC15863EC84DCD3770A2 /* TerminalAndGhosttyTests.swift in Sources */,
+				D0B10008A1B2C3D4E5F60001 /* PortalTabDragRoutingTests.swift in Sources */,
 				6B524A0BA34FD46A771335AB /* WorkspaceUnitTests.swift in Sources */,
 				063BC42CEE257D6213A2E30C /* WindowAndDragTests.swift in Sources */,
 				1521D55DC63D5E5FC4955E31 /* ShortcutAndCommandPaletteTests.swift in Sources */,

Sources/BonsplitTabBarPassThrough.swift

@@ -0,0 +1,115 @@
+import AppKit
+import Bonsplit
+
+/// Shared helpers for portal hosts that must defer to the minimal-mode
+/// Bonsplit tab strip rendered underneath them.
+enum BonsplitTabBarPassThrough {
+    static func isPassThroughPointerEvent(_ eventType: NSEvent.EventType?) -> Bool {
+        switch eventType {
+        case nil:
+            // Unit tests can call hitTest directly without an active AppKit event.
+            return true
+        case .leftMouseDown, .leftMouseUp, .leftMouseDragged,
+             .rightMouseDown, .rightMouseUp, .rightMouseDragged,
+             .otherMouseDown, .otherMouseUp, .otherMouseDragged,
+             .mouseMoved, .mouseEntered,
+             .mouseExited, .cursorUpdate,
+             .appKitDefined, .applicationDefined, .systemDefined, .periodic:
+            return true
+        default:
+            return false
+        }
+    }
+
+    static func titlebarInteractionBandMinY(in window: NSWindow) -> CGFloat {
+        let nativeTitlebarHeight = window.frame.height - window.contentLayoutRect.height
+        let customTitlebarBandHeight = max(28, min(72, nativeTitlebarHeight))
+        return window.contentLayoutRect.maxY - customTitlebarBandHeight - 0.5
+    }
+
+    // The minimal-mode tab strip lives just under the titlebar. Anything more
+    // than this many points below the content top can't overlap it, so we skip
+    // the recursive subtree scan on the pointer-event hot path.
+    private static let tabStripScanBandHeight: CGFloat = 200
+
+    static func shouldPassThroughToPaneTabBar(
+        windowPoint: NSPoint,
+        below portalHost: NSView
+    ) -> (result: Bool, registryHit: Bool) {
+        let registryHit = portalHost.window.map {
+            BonsplitTabBarHitRegionRegistry.containsWindowPoint(windowPoint, in: $0)
+        } ?? false
+        if registryHit {
+            return (true, true)
+        }
+
+        // High-frequency pointer events (mouseMoved/cursorUpdate) flow through
+        // here on every hover; cap the recursive view-tree walk to the top
+        // band where the tab strip can actually live.
+        if let window = portalHost.window {
+            let scanFloor = window.contentLayoutRect.maxY - tabStripScanBandHeight
+            if windowPoint.y < scanFloor {
+                return (false, false)
+            }
+        }
+
+        let fallbackHit = hasUnderlyingBonsplitTabBarBackground(
+            at: windowPoint,
+            below: portalHost
+        )
+        return (fallbackHit, false)
+    }
+
+    static func passThroughDecision(
+        at point: NSPoint,
+        in portalHost: NSView,
+        eventType: NSEvent.EventType?
+    ) -> (windowPoint: NSPoint, result: Bool, registryHit: Bool)? {
+        guard isPassThroughPointerEvent(eventType) else { return nil }
+        let windowPoint = portalHost.convert(point, to: nil)
+        let decision = shouldPassThroughToPaneTabBar(windowPoint: windowPoint, below: portalHost)
+        return (windowPoint, decision.result, decision.registryHit)
+    }
+
+    static func hasBonsplitTabBarBackground(at windowPoint: NSPoint, in view: NSView) -> Bool {
+        guard !view.isHidden, view.alphaValue > 0 else { return false }
+
+        // NSView subviews are not clipped to parent bounds by default, and the
+        // minimal tab strip can render outside its immediate container.
+        let className = NSStringFromClass(type(of: view))
+        if className.contains("TabBarBackgroundNSView") {
+            let pointInView = view.convert(windowPoint, from: nil)
+            if view.bounds.contains(pointInView) {
+                return true
+            }
+        }
+
+        for subview in view.subviews.reversed() {
+            if hasBonsplitTabBarBackground(at: windowPoint, in: subview) {
+                return true
+            }
+        }
+        return false
+    }
+
+    static func hasUnderlyingBonsplitTabBarBackground(
+        at windowPoint: NSPoint,
+        below portalHost: NSView
+    ) -> Bool {
+        // Only walk siblings rendered below the host. Falling back to the full
+        // window content tree when the host has no superview would risk a
+        // false-positive pass-through against a tab bar painted above an
+        // unparented host.
+        guard let container = portalHost.superview,
+              let hostIndex = container.subviews.firstIndex(of: portalHost) else {
+            return false
+        }
+        for sibling in container.subviews[..<hostIndex].reversed() {
+            guard !sibling.isHidden, sibling.alphaValue > 0 else { continue }
+            if hasBonsplitTabBarBackground(at: windowPoint, in: sibling) {
+                return true
+            }
+        }
+        return false
+    }
+}