diff --git a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
index 4bb703a1..c7b16c5e 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
@@ -45,6 +45,7 @@ public protocol PrefMgrProtocol {
   var alwaysShowTooltipTextsHorizontally: Bool { get set }
   var clientsIMKTextInputIncapable: [String: Bool] { get set }
   var onlyLoadFactoryLangModelsIfNeeded: Bool { get set }
+  var useSpaceToCommitHighlightedSCPCCandidate: Bool { get set }
   var useIMKCandidateWindow: Bool { get set }
   var enableSwiftUIForTDKCandidates: Bool { get set }
   var enableMouseScrollingForTDKCandidatesCocoa: Bool { get set }
diff --git a/Packages/vChewing_Shared/Sources/Shared/Shared.swift b/Packages/vChewing_Shared/Sources/Shared/Shared.swift
index a452d26e..267d2e88 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Shared.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Shared.swift
@@ -74,6 +74,7 @@ public enum UserDef: String, CaseIterable {
   case kPhraseEditorAutoReloadExternalModifications = "PhraseEditorAutoReloadExternalModifications"
   case kClassicHaninKeyboardSymbolModeShortcutEnabled = "ClassicHaninKeyboardSymbolModeShortcutEnabled"
 
+  case kUseSpaceToCommitHighlightedSCPCCandidate = "UseSpaceToCommitHighlightedSCPCCandidate"
   case kUseIMKCandidateWindow = "UseIMKCandidateWindow"
   case kEnableSwiftUIForTDKCandidates = "EnableSwiftUIForTDKCandidates"
   case kEnableMouseScrollingForTDKCandidatesCocoa = "EnableMouseScrollingForTDKCandidatesCocoa"
diff --git a/Source/Modules/PrefMgr_Core.swift b/Source/Modules/PrefMgr_Core.swift
index 6ab7bb8c..4bcc2a4a 100644
--- a/Source/Modules/PrefMgr_Core.swift
+++ b/Source/Modules/PrefMgr_Core.swift
@@ -182,6 +182,9 @@ public class PrefMgr: PrefMgrProtocol {
 
   // MARK: - Settings (Tier 2)
 
+  @AppProperty(key: UserDef.kUseSpaceToCommitHighlightedSCPCCandidate.rawValue, defaultValue: true)
+  public var useSpaceToCommitHighlightedSCPCCandidate: Bool
+
   @AppProperty(key: UserDef.kUseIMKCandidateWindow.rawValue, defaultValue: false)
   public var useIMKCandidateWindow: Bool