diff --git a/GhosttyTabs.xcodeproj/project.pbxproj b/GhosttyTabs.xcodeproj/project.pbxproj
index 0b100e14..7a798706 100644
--- a/GhosttyTabs.xcodeproj/project.pbxproj
+++ b/GhosttyTabs.xcodeproj/project.pbxproj
@@ -55,7 +55,7 @@
 		A5001208 /* UpdateTitlebarAccessory.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5001218 /* UpdateTitlebarAccessory.swift */; };
 		A5001209 /* WindowToolbarController.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5001219 /* WindowToolbarController.swift */; };
 		A5001240 /* WindowDecorationsController.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5001241 /* WindowDecorationsController.swift */; };
-		A5001600 /* SessionPersistence.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5001601 /* SessionPersistence.swift */; };
+		A5001610 /* SessionPersistence.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5001611 /* SessionPersistence.swift */; };
 		A5001100 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = A5001101 /* Assets.xcassets */; };
 		A5001230 /* Sparkle in Frameworks */ = {isa = PBXBuildFile; productRef = A5001231 /* Sparkle */; };
 		B9000002A1B2C3D4E5F60719 /* cmux.swift in Sources */ = {isa = PBXBuildFile; fileRef = B9000001A1B2C3D4E5F60719 /* cmux.swift */; };
@@ -184,7 +184,7 @@
 		A5001222 /* WindowAccessor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WindowAccessor.swift; sourceTree = "<group>"; };
 		A5001223 /* UpdateLogStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Update/UpdateLogStore.swift; sourceTree = "<group>"; };
 		A5001241 /* WindowDecorationsController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WindowDecorationsController.swift; sourceTree = "<group>"; };
-		A5001601 /* SessionPersistence.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SessionPersistence.swift; sourceTree = "<group>"; };
+		A5001611 /* SessionPersistence.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SessionPersistence.swift; sourceTree = "<group>"; };
 		818DBCD4AB69EB72573E8138 /* SidebarResizeUITests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SidebarResizeUITests.swift; sourceTree = "<group>"; };
 		C0B4D9B1A1B2C3D4E5F60718 /* UpdatePillUITests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UpdatePillUITests.swift; sourceTree = "<group>"; };
 		A5001101 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
@@ -357,7 +357,7 @@
 				A5001219 /* WindowToolbarController.swift */,
 				A5001241 /* WindowDecorationsController.swift */,
 				A5001222 /* WindowAccessor.swift */,
-				A5001601 /* SessionPersistence.swift */,
+				A5001611 /* SessionPersistence.swift */,
 			);
 			path = Sources;
 			sourceTree = "<group>";
@@ -590,7 +590,7 @@
 				A5001209 /* WindowToolbarController.swift in Sources */,
 				A5001240 /* WindowDecorationsController.swift in Sources */,
 				A500120C /* WindowAccessor.swift in Sources */,
-				A5001600 /* SessionPersistence.swift in Sources */,
+				A5001610 /* SessionPersistence.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/Sources/SessionPersistence.swift b/Sources/SessionPersistence.swift
index f4459a68..d660d467 100644
--- a/Sources/SessionPersistence.swift
+++ b/Sources/SessionPersistence.swift
@@ -322,6 +322,7 @@ indirect enum SessionWorkspaceLayoutSnapshot: Codable, Sendable {
 struct SessionWorkspaceSnapshot: Codable, Sendable {
     var processTitle: String
     var customTitle: String?
+    var customColor: String?
     var isPinned: Bool
     var currentDirectory: String
     var focusedPanelId: UUID?
diff --git a/Sources/Workspace.swift b/Sources/Workspace.swift
index a9b8021c..1fda66ce 100644
--- a/Sources/Workspace.swift
+++ b/Sources/Workspace.swift
@@ -118,6 +118,7 @@ extension Workspace {
         return SessionWorkspaceSnapshot(
             processTitle: processTitle,
             customTitle: customTitle,
+            customColor: customColor,
             isPinned: isPinned,
             currentDirectory: currentDirectory,
             focusedPanelId: focusedPanelId,
@@ -156,6 +157,7 @@ extension Workspace {
 
         applyProcessTitle(snapshot.processTitle)
         setCustomTitle(snapshot.customTitle)
+        setCustomColor(snapshot.customColor)
         isPinned = snapshot.isPinned
 
         statusEntries = Dictionary(
@@ -1323,7 +1325,11 @@ final class Workspace: Identifiable, ObservableObject {
     }
 
     func setCustomColor(_ hex: String?) {
-        customColor = hex
+        if let hex {
+            customColor = WorkspaceTabColorSettings.normalizedHex(hex)
+        } else {
+            customColor = nil
+        }
     }
 
     func setCustomTitle(_ title: String?) {
diff --git a/cmuxTests/SessionPersistenceTests.swift b/cmuxTests/SessionPersistenceTests.swift
index 1fb01fa0..638e8794 100644
--- a/cmuxTests/SessionPersistenceTests.swift
+++ b/cmuxTests/SessionPersistenceTests.swift
@@ -25,6 +25,38 @@ final class SessionPersistenceTests: XCTestCase {
         XCTAssertEqual(loaded?.windows.first?.sidebar.selection, .tabs)
     }
 
+    func testSaveAndLoadRoundTripPreservesWorkspaceCustomColor() {
+        let tempDir = FileManager.default.temporaryDirectory
+            .appendingPathComponent("cmux-session-tests-\(UUID().uuidString)", isDirectory: true)
+        try? FileManager.default.createDirectory(at: tempDir, withIntermediateDirectories: true)
+        defer { try? FileManager.default.removeItem(at: tempDir) }
+
+        let snapshotURL = tempDir.appendingPathComponent("session.json", isDirectory: false)
+        var snapshot = makeSnapshot(version: SessionSnapshotSchema.currentVersion)
+        snapshot.windows[0].tabManager.workspaces[0].customColor = "#C0392B"
+
+        XCTAssertTrue(SessionPersistenceStore.save(snapshot, fileURL: snapshotURL))
+
+        let loaded = SessionPersistenceStore.load(fileURL: snapshotURL)
+        XCTAssertEqual(
+            loaded?.windows.first?.tabManager.workspaces.first?.customColor,
+            "#C0392B"
+        )
+    }
+
+    func testWorkspaceCustomColorDecodeSupportsMissingLegacyField() throws {
+        var snapshot = makeSnapshot(version: SessionSnapshotSchema.currentVersion)
+        snapshot.windows[0].tabManager.workspaces[0].customColor = nil
+
+        let encoder = JSONEncoder()
+        let data = try encoder.encode(snapshot)
+        let json = try XCTUnwrap(String(data: data, encoding: .utf8))
+        XCTAssertFalse(json.contains("\"customColor\""))
+
+        let decoded = try JSONDecoder().decode(AppSessionSnapshot.self, from: data)
+        XCTAssertNil(decoded.windows.first?.tabManager.workspaces.first?.customColor)
+    }
+
     func testLoadRejectsSchemaVersionMismatch() {
         let tempDir = FileManager.default.temporaryDirectory
             .appendingPathComponent("cmux-session-tests-\(UUID().uuidString)", isDirectory: true)
@@ -442,6 +474,7 @@ final class SessionPersistenceTests: XCTestCase {
         let workspace = SessionWorkspaceSnapshot(
             processTitle: "Terminal",
             customTitle: "Restored",
+            customColor: nil,
             isPinned: true,
             currentDirectory: "/tmp",
             focusedPanelId: nil,