diff --git a/Source/Modules/ControllerModules/KeyHandler_States.swift b/Source/Modules/ControllerModules/KeyHandler_States.swift
index 9da6c54a..82b76b1d 100644
--- a/Source/Modules/ControllerModules/KeyHandler_States.swift
+++ b/Source/Modules/ControllerModules/KeyHandler_States.swift
@@ -113,8 +113,19 @@ extension KeyHandler {
     let composedText = head + reading + tail
     let cursorIndex = composedStringCursorIndex + reading.utf16.count
 
+    var cleanedComposition = ""
+
+    // 防止組字區內出現不可列印的字元。
+    for theChar in composedText {
+      if let charCode = theChar.utf16.first {
+        if !(theChar.isASCII && !(charCode.isPrintable())) {
+          cleanedComposition += String(theChar)
+        }
+      }
+    }
+
     /// 這裡生成準備要拿來回呼的「正在輸入」狀態，但還不能立即使用，因為工具提示仍未完成。
-    let stateResult = InputState.Inputting(composingBuffer: composedText, cursorIndex: cursorIndex)
+    let stateResult = InputState.Inputting(composingBuffer: cleanedComposition, cursorIndex: cursorIndex)
 
     /// 根據上文的參數結果來決定生成怎樣的工具提示。
     switch (tooltipParameterRef[0].isEmpty, tooltipParameterRef[1].isEmpty) {
diff --git a/Source/Modules/ControllerModules/ctlInputMethod_Core.swift b/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
index 55d8161e..d4ab7717 100644
--- a/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
+++ b/Source/Modules/ControllerModules/ctlInputMethod_Core.swift
@@ -303,19 +303,8 @@ extension ctlInputMethod {
       return
     }
 
-    var bufferOutput = ""
-
-    // 防止輸入法輸出不可列印的字元。
-    for theChar in buffer {
-      if let charCode = theChar.utf16.first {
-        if !(theChar.isASCII && !(charCode.isPrintable())) {
-          bufferOutput += String(theChar)
-        }
-      }
-    }
-
     client().insertText(
-      bufferOutput, replacementRange: NSRange(location: NSNotFound, length: NSNotFound)
+      buffer, replacementRange: NSRange(location: NSNotFound, length: NSNotFound)
     )
   }