From 79cfe2d1682443703671b03e4eedf6ea869e9c9f Mon Sep 17 00:00:00 2001
From: Lawrence Chen <54008264+lawrencecchen@users.noreply.github.com>
Date: Wed, 4 Mar 2026 02:48:06 -0800
Subject: [PATCH] Fix cross-window theme background gating after jump-to-unread
 (#861)

* Fix cross-window theme background gating

* Handle owning-manager nil-selection theme edge case

* Simplify window background gating helper
---
 Sources/GhosttyTerminalView.swift  | 31 +++++++++-
 cmuxTests/GhosttyConfigTests.swift | 90 ++++++++++++++++++++++++++++++
 2 files changed, 120 insertions(+), 1 deletion(-)

diff --git a/Sources/GhosttyTerminalView.swift b/Sources/GhosttyTerminalView.swift
index 3de0ee2a..020d4ad7 100644
--- a/Sources/GhosttyTerminalView.swift
+++ b/Sources/GhosttyTerminalView.swift
@@ -2981,9 +2981,38 @@ class GhosttyNSView: NSView, NSUserInterfaceValidations {
         }
     }
 
+    // Theme/background application is window-local. During cross-window workspace
+    // switches (e.g. jump-to-unread), the global active tab manager can lag behind.
+    // Prefer the owning window's selected workspace when available.
+    static func shouldApplyWindowBackground(
+        surfaceTabId: UUID?,
+        owningManagerExists: Bool,
+        owningSelectedTabId: UUID?,
+        activeSelectedTabId: UUID?
+    ) -> Bool {
+        guard let surfaceTabId else { return true }
+        if owningManagerExists {
+            guard let owningSelectedTabId else { return true }
+            return owningSelectedTabId == surfaceTabId
+        }
+        if let activeSelectedTabId {
+            return activeSelectedTabId == surfaceTabId
+        }
+        return true
+    }
+
     func applyWindowBackgroundIfActive() {
         guard let window else { return }
-        if let tabId, let selectedId = AppDelegate.shared?.tabManager?.selectedTabId, tabId != selectedId {
+        let appDelegate = AppDelegate.shared
+        let owningManager = tabId.flatMap { appDelegate?.tabManagerFor(tabId: $0) }
+        let owningSelectedTabId = owningManager?.selectedTabId
+        let activeSelectedTabId = owningManager == nil ? appDelegate?.tabManager?.selectedTabId : nil
+        guard Self.shouldApplyWindowBackground(
+            surfaceTabId: tabId,
+            owningManagerExists: owningManager != nil,
+            owningSelectedTabId: owningSelectedTabId,
+            activeSelectedTabId: activeSelectedTabId
+        ) else {
             return
         }
         applySurfaceBackground()
diff --git a/cmuxTests/GhosttyConfigTests.swift b/cmuxTests/GhosttyConfigTests.swift
index ac9d68b7..98bff922 100644
--- a/cmuxTests/GhosttyConfigTests.swift
+++ b/cmuxTests/GhosttyConfigTests.swift
@@ -659,6 +659,96 @@ final class WindowTransparencyDecisionTests: XCTestCase {
     }
 }
 
+final class WindowBackgroundSelectionGateTests: XCTestCase {
+    func testShouldApplyWindowBackgroundUsesOwningWindowSelectionWhenAvailable() {
+        let tabId = UUID()
+        let activeSelectedTabId = UUID()
+
+        XCTAssertTrue(
+            GhosttyNSView.shouldApplyWindowBackground(
+                surfaceTabId: tabId,
+                owningManagerExists: true,
+                owningSelectedTabId: tabId,
+                activeSelectedTabId: activeSelectedTabId
+            )
+        )
+    }
+
+    func testShouldApplyWindowBackgroundRejectsWhenOwningSelectionDiffers() {
+        let tabId = UUID()
+
+        XCTAssertFalse(
+            GhosttyNSView.shouldApplyWindowBackground(
+                surfaceTabId: tabId,
+                owningManagerExists: true,
+                owningSelectedTabId: UUID(),
+                activeSelectedTabId: tabId
+            )
+        )
+    }
+
+    func testShouldApplyWindowBackgroundAllowsWhenOwningManagerSelectionIsTemporarilyNil() {
+        let tabId = UUID()
+
+        XCTAssertTrue(
+            GhosttyNSView.shouldApplyWindowBackground(
+                surfaceTabId: tabId,
+                owningManagerExists: true,
+                owningSelectedTabId: nil,
+                activeSelectedTabId: UUID()
+            )
+        )
+    }
+
+    func testShouldApplyWindowBackgroundFallsBackToActiveSelection() {
+        let tabId = UUID()
+
+        XCTAssertTrue(
+            GhosttyNSView.shouldApplyWindowBackground(
+                surfaceTabId: tabId,
+                owningManagerExists: false,
+                owningSelectedTabId: nil,
+                activeSelectedTabId: tabId
+            )
+        )
+        XCTAssertFalse(
+            GhosttyNSView.shouldApplyWindowBackground(
+                surfaceTabId: tabId,
+                owningManagerExists: false,
+                owningSelectedTabId: nil,
+                activeSelectedTabId: UUID()
+            )
+        )
+    }
+
+    func testShouldApplyWindowBackgroundAllowsWhenNoSelectionContext() {
+        XCTAssertTrue(
+            GhosttyNSView.shouldApplyWindowBackground(
+                surfaceTabId: UUID(),
+                owningManagerExists: false,
+                owningSelectedTabId: nil,
+                activeSelectedTabId: nil
+            )
+        )
+        XCTAssertTrue(
+            GhosttyNSView.shouldApplyWindowBackground(
+                surfaceTabId: nil,
+                owningManagerExists: false,
+                owningSelectedTabId: nil,
+                activeSelectedTabId: nil
+            )
+        )
+        XCTAssertTrue(
+            GhosttyNSView.shouldApplyWindowBackground(
+                surfaceTabId: nil,
+                owningManagerExists: true,
+                owningSelectedTabId: UUID(),
+                activeSelectedTabId: UUID()
+            )
+        )
+    }
+}
+
 final class NotificationBurstCoalescerTests: XCTestCase {
     func testSignalsInSameBurstFlushOnce() {
         let coalescer = NotificationBurstCoalescer(delay: 0.01)