diff --git a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
index 1cd57c99..2d3be9d3 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
@@ -54,6 +54,7 @@ public protocol PrefMgrProtocol {
   var showReverseLookupInCandidateUI: Bool { get set }
   var autoCompositeWithLongestPossibleCassetteKey: Bool { get set }
   var shareAlphanumericalModeStatusAcrossClients: Bool { get set }
+  var phraseEditorAutoReloadExternalModifications: Bool { get set }
   var cns11643Enabled: Bool { get set }
   var cassetteEnabled: Bool { get set }
   var symbolInputEnabled: Bool { get set }
diff --git a/Packages/vChewing_Shared/Sources/Shared/Shared.swift b/Packages/vChewing_Shared/Sources/Shared/Shared.swift
index 04c2a039..daf0613a 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Shared.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Shared.swift
@@ -67,6 +67,7 @@ public enum UserDef: String, CaseIterable {
   case kShowReverseLookupInCandidateUI = "ShowReverseLookupInCandidateUI"
   case kAutoCompositeWithLongestPossibleCassetteKey = "AutoCompositeWithLongestPossibleCassetteKey"
   case kShareAlphanumericalModeStatusAcrossClients = "ShareAlphanumericalModeStatusAcrossClients"
+  case kPhraseEditorAutoReloadExternalModifications = "PhraseEditorAutoReloadExternalModifications"
 
   case kUseIMKCandidateWindow = "UseIMKCandidateWindow"
   case kHandleDefaultCandidateFontsByLangIdentifier = "HandleDefaultCandidateFontsByLangIdentifier"
diff --git a/Source/Modules/PrefMgr_Core.swift b/Source/Modules/PrefMgr_Core.swift
index 81c8a1a1..45a4fa19 100644
--- a/Source/Modules/PrefMgr_Core.swift
+++ b/Source/Modules/PrefMgr_Core.swift
@@ -155,6 +155,9 @@ public class PrefMgr: PrefMgrProtocol {
   @AppProperty(key: UserDef.kShareAlphanumericalModeStatusAcrossClients.rawValue, defaultValue: false)
   public var shareAlphanumericalModeStatusAcrossClients: Bool
 
+  @AppProperty(key: UserDef.kPhraseEditorAutoReloadExternalModifications.rawValue, defaultValue: true)
+  public var phraseEditorAutoReloadExternalModifications: Bool
+
   // MARK: - Settings (Tier 2)
 
   @AppProperty(key: UserDef.kUseIMKCandidateWindow.rawValue, defaultValue: false)