diff --git a/Source/Modules/ControllerModules/KeyHandler_Core.swift b/Source/Modules/ControllerModules/KeyHandler_Core.swift
index 8ac1887d..09016f4c 100644
--- a/Source/Modules/ControllerModules/KeyHandler_Core.swift
+++ b/Source/Modules/ControllerModules/KeyHandler_Core.swift
@@ -19,6 +19,7 @@ import Foundation
 /// KeyHandler 委任協定
 protocol KeyHandlerDelegate {
   var clientBundleIdentifier: String { get }
+  var isVerticalTyping: Bool { get }
   func ctlCandidate() -> ctlCandidateProtocol
   func keyHandler(
     _: KeyHandler, didSelectCandidateAt index: Int,
diff --git a/Source/Modules/ControllerModules/ctlInputMethod_Core.swift b/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
index 99cf1603..dab2ccf2 100644
--- a/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
+++ b/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
@@ -39,16 +39,6 @@ class ctlInputMethod: IMKInputController {
   /// 當前這個 ctlInputMethod 副本是否處於英數輸入模式。
   var isASCIIMode: Bool = false
 
-  /// 記錄當前輸入環境是縱排輸入還是橫排輸入。
-  public var isVerticalTyping: Bool {
-    guard let client = client() else { return false }
-    var textFrame = NSRect.zero
-    let attributes: [AnyHashable: Any]? = client.attributes(
-      forCharacterIndex: 0, lineHeightRectangle: &textFrame
-    )
-    return (attributes?["IMKTextOrientation"] as? NSNumber)?.intValue == 0 || false
-  }
-
   /// 切換當前 ctlInputMethod 副本的英數輸入模式開關。
   func toggleASCIIMode() -> Bool {
     resetKeyHandler()
diff --git a/Source/Modules/ControllerModules/ctlInputMethod_Delegates.swift b/Source/Modules/ControllerModules/ctlInputMethod_Delegates.swift
index 1d634e75..d0746aa4 100644
--- a/Source/Modules/ControllerModules/ctlInputMethod_Delegates.swift
+++ b/Source/Modules/ControllerModules/ctlInputMethod_Delegates.swift
@@ -13,6 +13,16 @@ import Cocoa
 // MARK: - KeyHandler Delegate
 
 extension ctlInputMethod: KeyHandlerDelegate {
+  /// 記錄當前輸入環境是縱排輸入還是橫排輸入。
+  public var isVerticalTyping: Bool {
+    guard let client = client() else { return false }
+    var textFrame = NSRect.zero
+    let attributes: [AnyHashable: Any]? = client.attributes(
+      forCharacterIndex: 0, lineHeightRectangle: &textFrame
+    )
+    return (attributes?["IMKTextOrientation"] as? NSNumber)?.intValue == 0 || false
+  }
+
   var clientBundleIdentifier: String {
     guard let client = client() else { return "" }
     return client.bundleIdentifier() ?? ""