diff --git a/NEWS.md b/NEWS.md
index d8b71601..0e2c4367 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -18,6 +18,7 @@ Red Panda C++ Version 0.14.5
   - fix: the scroll speed of mouse selection/drag is too fast.
   - fix: the scroll behavior of mouse dragging on the editor's edge is not correct
   - fix: calculation of caret position is not in consistence.
+  - fix: undo one symbol completion as a whole operation
 
 Red Panda C++ Version 0.14.4
   - enhancement: git - log
diff --git a/RedPandaIDE/editor.cpp b/RedPandaIDE/editor.cpp
index 9de1a001..66b586de 100644
--- a/RedPandaIDE/editor.cpp
+++ b/RedPandaIDE/editor.cpp
@@ -2053,10 +2053,12 @@ bool Editor::handleParentheseCompletion()
     QuoteStatus status = getQuoteStatus();
     if (status == QuoteStatus::RawString || status == QuoteStatus::NotQuote) {
         beginUpdate();
+        beginUndoBlock();
         commandProcessor(SynEditorCommand::ecChar,'(');
         BufferCoord oldCaret = caretXY();
         commandProcessor(SynEditorCommand::ecChar,')');
         setCaretXY(oldCaret);
+        endUndoBlock();
         endUpdate();
         return true;
     }
@@ -2102,10 +2104,12 @@ bool Editor::handleBracketCompletion()
 //    QuoteStatus status = getQuoteStatus();
 //    if (status == QuoteStatus::RawString || status == QuoteStatus::NotQuote) {
     beginUpdate();
+    beginUndoBlock();
     commandProcessor(SynEditorCommand::ecChar,'[');
     BufferCoord oldCaret = caretXY();
     commandProcessor(SynEditorCommand::ecChar,']');
     setCaretXY(oldCaret);
+    endUndoBlock();
     endUpdate();
     return true;
         //    }
@@ -2136,11 +2140,13 @@ bool Editor::handleMultilineCommentCompletion()
 {
     if ((caretX()-2 < lineText().length()) && (lineText()[caretX() - 2] == '/')) {
         beginUpdate();
+        beginUndoBlock();
         commandProcessor(SynEditorCommand::ecChar,'*');
         BufferCoord oldCaret = caretXY();
         commandProcessor(SynEditorCommand::ecChar,'*');
         commandProcessor(SynEditorCommand::ecChar,'/');
         setCaretXY(oldCaret);
+        endUndoBlock();
         endUpdate();
         return true;
     }
@@ -2156,6 +2162,7 @@ bool Editor::handleBraceCompletion()
         i--;
     }
     beginUpdate();
+    beginUndoBlock();
     commandProcessor(SynEditorCommand::ecChar,'{');
     BufferCoord oldCaret = caretXY();
     commandProcessor(SynEditorCommand::ecChar,'}');
@@ -2172,6 +2179,7 @@ bool Editor::handleBraceCompletion()
         commandProcessor(SynEditorCommand::ecChar,';');
     }
     setCaretXY(oldCaret);
+    endUndoBlock();
     endUpdate();
     return true;
 }
@@ -2218,10 +2226,12 @@ bool Editor::handleSingleQuoteCompletion()
             if (ch == 0 || highlighter()->isWordBreakChar(ch) || highlighter()->isSpaceChar(ch)) {
                 // insert ''
                 beginUpdate();
+                beginUndoBlock();
                 commandProcessor(SynEditorCommand::ecChar,'\'');
                 BufferCoord oldCaret = caretXY();
                 commandProcessor(SynEditorCommand::ecChar,'\'');
                 setCaretXY(oldCaret);
+                endUndoBlock();
                 endUpdate();
                 return true;
             }
@@ -2244,10 +2254,12 @@ bool Editor::handleDoubleQuoteCompletion()
             if ((ch == 0) || highlighter()->isWordBreakChar(ch) || highlighter()->isSpaceChar(ch)) {
                 // insert ""
                 beginUpdate();
+                beginUndoBlock();
                 commandProcessor(SynEditorCommand::ecChar,'"');
                 BufferCoord oldCaret = caretXY();
                 commandProcessor(SynEditorCommand::ecChar,'"');
                 setCaretXY(oldCaret);
+                endUndoBlock();
                 endUpdate();
                 return true;
             }
@@ -2264,11 +2276,13 @@ bool Editor::handleGlobalIncludeCompletion()
     if (!s.startsWith("include"))  //it's not #include
         return false;
     beginUpdate();
+    beginUndoBlock();
     commandProcessor(SynEditorCommand::ecChar,'<');
     BufferCoord oldCaret = caretXY();
     commandProcessor(SynEditorCommand::ecChar,'>');
     setCaretXY(oldCaret);
     endUpdate();
+    endUndoBlock();
     return true;
 }
 
diff --git a/RedPandaIDE/qsynedit/SynEdit.cpp b/RedPandaIDE/qsynedit/SynEdit.cpp
index 1bc05bca..804f12e0 100644
--- a/RedPandaIDE/qsynedit/SynEdit.cpp
+++ b/RedPandaIDE/qsynedit/SynEdit.cpp
@@ -441,6 +441,16 @@ bool SynEdit::getHighlighterAttriAtRowColEx(const BufferCoord &XY, QString &Toke
     return false;
 }
 
+void SynEdit::beginUndoBlock()
+{
+    mUndoList->BeginBlock();
+}
+
+void SynEdit::endUndoBlock()
+{
+    mUndoList->EndBlock();
+}
+
 void SynEdit::beginUpdate()
 {
     incPaintLock();
diff --git a/RedPandaIDE/qsynedit/SynEdit.h b/RedPandaIDE/qsynedit/SynEdit.h
index 30f940eb..24d2029e 100644
--- a/RedPandaIDE/qsynedit/SynEdit.h
+++ b/RedPandaIDE/qsynedit/SynEdit.h
@@ -259,6 +259,9 @@ public:
       SynHighlighterTokenType& TokenType, SynTokenKind &TokenKind, int &Start,
       PSynHighlighterAttribute& Attri);
 
+    void beginUndoBlock();
+    void endUndoBlock();
+
     //Commands
     virtual void cutToClipboard() { commandProcessor(SynEditorCommand::ecCut);}
     virtual void copyToClipboard() { commandProcessor(SynEditorCommand::ecCopy);}