diff --git a/Source/Modules/ControllerModules/InputState.swift b/Source/Modules/ControllerModules/InputState.swift
index 0b9b5d24..ee285409 100644
--- a/Source/Modules/ControllerModules/InputState.swift
+++ b/Source/Modules/ControllerModules/InputState.swift
@@ -137,6 +137,15 @@ class InputState {
   class NotEmpty: InputState {
     private(set) var composingBuffer: String
     private(set) var cursorIndex: Int = 0 { didSet { cursorIndex = max(cursorIndex, 0) } }
+    var composingBufferConverted: String {
+      let converted = IME.kanjiConversionIfRequired(composingBuffer)
+      if converted.utf16.count != composingBuffer.utf16.count
+        || converted.count != composingBuffer.count
+      {
+        return composingBuffer
+      }
+      return converted
+    }
 
     init(composingBuffer: String, cursorIndex: Int) {
       self.composingBuffer = composingBuffer
@@ -145,8 +154,10 @@ class InputState {
     }
 
     var attributedString: NSAttributedString {
+      /// 考慮到因為滑鼠點擊等其它行為導致的組字區內容遞交情況，
+      /// 這裡對組字區內容也加上康熙字轉換或者 JIS 漢字轉換處理。
       let attributedString = NSAttributedString(
-        string: IME.kanjiConversionIfRequired(composingBuffer),
+        string: composingBufferConverted,
         attributes: [
           .underlineStyle: NSUnderlineStyle.single.rawValue,
           .markedClauseSegment: 0,
@@ -260,7 +271,9 @@ class InputState {
     }
 
     override var attributedString: NSAttributedString {
-      let attributedString = NSMutableAttributedString(string: IME.kanjiConversionIfRequired(composingBuffer))
+      /// 考慮到因為滑鼠點擊等其它行為導致的組字區內容遞交情況，
+      /// 這裡對組字區內容也加上康熙字轉換或者 JIS 漢字轉換處理。
+      let attributedString = NSMutableAttributedString(string: composingBufferConverted)
       let end = markedRange.upperBound
 
       attributedString.setAttributes(
diff --git a/Source/Modules/ControllerModules/KeyHandler_Core.swift b/Source/Modules/ControllerModules/KeyHandler_Core.swift
index 1cf5db7b..604d7845 100644
--- a/Source/Modules/ControllerModules/KeyHandler_Core.swift
+++ b/Source/Modules/ControllerModules/KeyHandler_Core.swift
@@ -446,19 +446,4 @@ class KeyHandler {
   func deleteCompositorReadingToTheFrontOfCursor() {
     compositor.deleteReadingToTheFrontOfCursor()
   }
-
-  // MARK: - 其他工具函式
-
-  func kanjiConversionIfRequired(_ text: String) -> String {
-    if inputMode == InputMode.imeModeCHT {
-      switch (mgrPrefs.chineseConversionEnabled, mgrPrefs.shiftJISShinjitaiOutputEnabled) {
-        case (false, true): return vChewingKanjiConverter.cnvTradToJIS(text)
-        case (true, false): return vChewingKanjiConverter.cnvTradToKangXi(text)
-        // 本來這兩個開關不該同時開啟的，但萬一被開啟了的話就這樣處理：
-        case (true, true): return vChewingKanjiConverter.cnvTradToJIS(text)
-        case (false, false): return text
-      }
-    }
-    return text
-  }
 }
diff --git a/Source/Modules/ControllerModules/ctlInputMethod_Core.swift b/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
index c9d35bd9..55d8161e 100644
--- a/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
+++ b/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
@@ -298,7 +298,7 @@ extension ctlInputMethod {
 
   /// 遞交組字區內容。
   private func commit(text: String) {
-    let buffer = keyHandler.kanjiConversionIfRequired(text)
+    let buffer = IME.kanjiConversionIfRequired(text)
     if buffer.isEmpty {
       return
     }
diff --git a/Source/Modules/IMEModules/IME.swift b/Source/Modules/IMEModules/IME.swift
index 47c35d22..05935c86 100644
--- a/Source/Modules/IMEModules/IME.swift
+++ b/Source/Modules/IMEModules/IME.swift
@@ -43,6 +43,19 @@ public enum IME {
 
   static var currentInputMode: InputMode = .init(rawValue: mgrPrefs.mostRecentInputMode) ?? .imeModeNULL
 
+  static func kanjiConversionIfRequired(_ text: String) -> String {
+    if currentInputMode == InputMode.imeModeCHT {
+      switch (mgrPrefs.chineseConversionEnabled, mgrPrefs.shiftJISShinjitaiOutputEnabled) {
+        case (false, true): return vChewingKanjiConverter.cnvTradToJIS(text)
+        case (true, false): return vChewingKanjiConverter.cnvTradToKangXi(text)
+        // 本來這兩個開關不該同時開啟的，但萬一被開啟了的話就這樣處理：
+        case (true, true): return vChewingKanjiConverter.cnvTradToJIS(text)
+        case (false, false): return text
+      }
+    }
+    return text
+  }
+
   // MARK: - 開關判定當前應用究竟是？
 
   static var areWeUsingOurOwnPhraseEditor: Bool = false