diff --git a/NEWS.md b/NEWS.md
index c598d9da..0f01c6e0 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,6 @@
 Version 0.6.8
  - enhancement: add link to cppreference in the help menu
+ - fix: add mutex lock to prevent editor crash in rare conditions
 
 Version 0.6.7
  - fix: messages send to the gdb process's standard error are not received
diff --git a/RedPandaIDE/cpprefacter.cpp b/RedPandaIDE/cpprefacter.cpp
index a48d14aa..4475cd8e 100644
--- a/RedPandaIDE/cpprefacter.cpp
+++ b/RedPandaIDE/cpprefacter.cpp
@@ -121,7 +121,7 @@ PSearchResultTreeItem CppRefacter::findOccurenceInFile(
         editor.lines()->setContents(buffer);
     } else {
         QByteArray encoding;
-        editor.lines()->LoadFromFile(filename,ENCODING_AUTO_DETECT,encoding);
+        editor.lines()->loadFromFile(filename,ENCODING_AUTO_DETECT,encoding);
     }
     editor.setHighlighter(HighlighterManager().getCppHighlighter());
     int posY = 0;
@@ -182,7 +182,7 @@ void CppRefacter::renameSymbolInFile(const QString &filename, const PStatement &
         editor.lines()->setContents(buffer);
     } else {
         QByteArray encoding;
-        editor.lines()->LoadFromFile(filename,ENCODING_AUTO_DETECT,encoding);
+        editor.lines()->loadFromFile(filename,ENCODING_AUTO_DETECT,encoding);
     }
     QStringList newContents;
     editor.setHighlighter(HighlighterManager().getCppHighlighter());
@@ -235,7 +235,7 @@ void CppRefacter::renameSymbolInFile(const QString &filename, const PStatement &
     } else {
         QByteArray realEncoding;
         QFile file(filename);
-        editor.lines()->SaveToFile(file,ENCODING_AUTO_DETECT, realEncoding);
+        editor.lines()->saveToFile(file,ENCODING_AUTO_DETECT, realEncoding);
     }
 }
 
diff --git a/RedPandaIDE/editor.cpp b/RedPandaIDE/editor.cpp
index 01cde49e..cdc7001f 100644
--- a/RedPandaIDE/editor.cpp
+++ b/RedPandaIDE/editor.cpp
@@ -163,9 +163,9 @@ Editor::~Editor() {
 
 void Editor::loadFile(const QString& filename) {
     if (filename.isEmpty()) {
-        this->lines()->LoadFromFile(mFilename,mEncodingOption,mFileEncoding);
+        this->lines()->loadFromFile(mFilename,mEncodingOption,mFileEncoding);
     } else {
-        this->lines()->LoadFromFile(filename,mEncodingOption,mFileEncoding);
+        this->lines()->loadFromFile(filename,mEncodingOption,mFileEncoding);
     }
     //this->setModified(false);
     updateCaption();
@@ -192,7 +192,7 @@ void Editor::loadFile(const QString& filename) {
 
 void Editor::saveFile(const QString &filename) {
     QFile file(filename);
-    this->lines()->SaveToFile(file,mEncodingOption,mFileEncoding);
+    this->lines()->saveToFile(file,mEncodingOption,mFileEncoding);
     pMainWindow->updateForEncodingInfo();
 }
 
diff --git a/RedPandaIDE/mainwindow.cpp b/RedPandaIDE/mainwindow.cpp
index e5947d35..1bbb75be 100644
--- a/RedPandaIDE/mainwindow.cpp
+++ b/RedPandaIDE/mainwindow.cpp
@@ -2032,6 +2032,8 @@ void MainWindow::openShell(const QString &folder, const QString &shellCommand)
 
 void MainWindow::onAutoSaveTimeout()
 {
+    if (mQuitting)
+        return;
     if (!pSettings->editor().enableAutoSave())
         return;
     int updateCount = 0;
@@ -2050,6 +2052,15 @@ void MainWindow::onAutoSaveTimeout()
         }
         break;
     case astAllProjectFiles:
+        if (!mProject)
+            return;
+        for (int i=0;i<mEditorList->pageCount();i++) {
+            Editor *e = (*mEditorList)[i];
+            if (!e->inProject())
+                return;
+            doAutoSave(e);
+            updateCount++;
+        }
         //todo: auto save project files
         break;
     }
diff --git a/RedPandaIDE/qsynedit/SynEdit.cpp b/RedPandaIDE/qsynedit/SynEdit.cpp
index ff05f4c0..51e19c3a 100644
--- a/RedPandaIDE/qsynedit/SynEdit.cpp
+++ b/RedPandaIDE/qsynedit/SynEdit.cpp
@@ -536,13 +536,11 @@ BufferCoord SynEdit::getMatchingBracketEx(BufferCoord APoint)
 
 QStringList SynEdit::contents()
 {
-    //QMutexLocker locker(&mMutex);
     return lines()->contents();
 }
 
 QString SynEdit::text()
 {
-    //QMutexLocker locker(&mMutex);
     return lines()->text();
 }
 
@@ -1750,7 +1748,7 @@ void SynEdit::doDuplicateLine()
 {
     if (!mReadOnly && (mLines->count() > 0)) {
         doOnPaintTransient(SynTransientType::ttBefore);
-        mLines->Insert(mCaretY, lineText());
+        mLines->insert(mCaretY, lineText());
         doLinesInserted(mCaretY + 1, 1);
         mUndoList->AddChange(SynChangeReason::crLineBreak,
                              caretXY(), caretXY(), "", SynSelectionMode::smNormal);
@@ -1774,7 +1772,7 @@ void SynEdit::doMoveSelUp()
         doLinesDeleted(OrigBlockBegin.Line - 1, 1); // before start, 1 based
 
         // Insert line below selection
-        mLines->Insert(OrigBlockEnd.Line - 1, s);
+        mLines->insert(OrigBlockEnd.Line - 1, s);
         doLinesInserted(OrigBlockEnd.Line, 1);
 
         // Restore caret and selection
@@ -1820,7 +1818,7 @@ void SynEdit::doMoveSelDown()
         doLinesDeleted(OrigBlockEnd.Line, 1); // before start, 1 based
 
         // Insert line above selection
-        mLines->Insert(OrigBlockBegin.Line - 1, s);
+        mLines->insert(OrigBlockBegin.Line - 1, s);
         doLinesInserted(OrigBlockBegin.Line, 1);
 
         // Restore caret and selection
@@ -1895,7 +1893,7 @@ void SynEdit::insertLine(bool moveCaret)
     if (Len > 0) {
         if (Len >= mCaretX) {
             if (mCaretX <= 1) {
-                mLines->Insert(mCaretY - 1, "");
+                mLines->insert(mCaretY - 1, "");
                 nLinesInserted++;
                 mUndoList->AddChange(SynChangeReason::crLineBreak, caretXY(), caretXY(), Temp2,
                                      SynSelectionMode::smNormal);
@@ -1925,7 +1923,7 @@ void SynEdit::insertLine(bool moveCaret)
                     }
                 }
                 QString indentSpacesForRightLineText = GetLeftSpacing(indentSpaces,true);
-                mLines->Insert(mCaretY, indentSpacesForRightLineText+rightLineText);
+                mLines->insert(mCaretY, indentSpacesForRightLineText+rightLineText);
                 nLinesInserted++;
 
                 //SpaceCount1 = mLines->getString(mCaretY).length(); //???
@@ -1936,7 +1934,7 @@ void SynEdit::insertLine(bool moveCaret)
                     indentSpaces = indentSpacesOfLeftLineText;
                     indentSpaces += mTabWidth;
                     indentSpacesForRightLineText = GetLeftSpacing(indentSpaces,true);
-                    mLines->Insert(mCaretY, indentSpacesForRightLineText);
+                    mLines->insert(mCaretY, indentSpacesForRightLineText);
                     nLinesInserted++;
                     mUndoList->AddChange(SynChangeReason::crLineBreak, caretXY(), caretXY(), "",
                             SynSelectionMode::smNormal);
@@ -1954,7 +1952,7 @@ void SynEdit::insertLine(bool moveCaret)
                     SpaceCount2 = leftSpaces(Temp);
                 } while ((BackCounter != 0) && (Temp == ""));
             }
-            mLines->Insert(mCaretY, "");
+            mLines->insert(mCaretY, "");
             nLinesInserted++;
             BufferCoord Caret = caretXY();
             if (moveCaret) {
@@ -1988,7 +1986,7 @@ void SynEdit::insertLine(bool moveCaret)
                 BackCounter--;
             }
         }
-        mLines->Insert(mCaretY - 1, "");
+        mLines->insert(mCaretY - 1, "");
         nLinesInserted++;
         mUndoList->AddChange(SynChangeReason::crLineBreak, caretXY(), caretXY(), "",
                              SynSelectionMode::smNormal);
@@ -4690,7 +4688,7 @@ int SynEdit::insertTextByNormalMode(const QString &Value)
     if (P<Value.length()) {
         Str = sLeftSide + Value.mid(0, P - Start);
         properSetLine(mCaretY - 1, Str);
-        mLines->InsertLines(mCaretY, CountLines(Value,P));
+        mLines->insertLines(mCaretY, CountLines(Value,P));
     } else {
         Str = sLeftSide + Value + sRightSide;
         properSetLine(mCaretY - 1, Str);
@@ -4810,7 +4808,7 @@ int SynEdit::insertTextByLineMode(const QString &Value)
         else
             Str = "";
         if ((mCaretY == mLines->count()) || mInserting) {
-            mLines->Insert(mCaretY - 1, "");
+            mLines->insert(mCaretY - 1, "");
             Result++;
         }
         properSetLine(mCaretY - 1, Str);
@@ -4886,7 +4884,6 @@ void SynEdit::onCommandProcessed(SynEditorCommand , QChar , void *)
 
 void SynEdit::ExecuteCommand(SynEditorCommand Command, QChar AChar, void *pData)
 {
-    QMutexLocker locker(&mMutex);
     incPaintLock();
     auto action=finally([this] {
         decPaintLock();
@@ -5924,8 +5921,6 @@ void SynEdit::setSelLength(int Value)
 
 void SynEdit::setSelText(const QString &text)
 {
-    QMutexLocker locker(&mMutex);
-
     doSetSelText(text);
 }
 
diff --git a/RedPandaIDE/qsynedit/SynEdit.h b/RedPandaIDE/qsynedit/SynEdit.h
index ae524d95..7dcf576e 100644
--- a/RedPandaIDE/qsynedit/SynEdit.h
+++ b/RedPandaIDE/qsynedit/SynEdit.h
@@ -5,7 +5,6 @@
 #include <QCursor>
 #include <QDateTime>
 #include <QFrame>
-#include <QMutex>
 #include <QStringList>
 #include <QTimer>
 #include <QWidget>
@@ -678,8 +677,6 @@ private:
 
     QString mInputPreeditString;
 
-    QRecursiveMutex mMutex;
-
 friend class SynEditTextPainter;
 
 // QWidget interface
diff --git a/RedPandaIDE/qsynedit/TextBuffer.cpp b/RedPandaIDE/qsynedit/TextBuffer.cpp
index c69d96a2..127fc019 100644
--- a/RedPandaIDE/qsynedit/TextBuffer.cpp
+++ b/RedPandaIDE/qsynedit/TextBuffer.cpp
@@ -3,6 +3,7 @@
 #include <QFile>
 #include <QTextCodec>
 #include <QTextStream>
+#include <QMutexLocker>
 #include <stdexcept>
 #include "SynEdit.h"
 #include "../utils.h"
@@ -25,24 +26,27 @@ static void ListIndexOutOfBounds(int index) {
 
 
 
-int SynEditStringList::parenthesisLevels(int Index) const
+int SynEditStringList::parenthesisLevels(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index>=0 && Index < mList.size()) {
         return mList[Index]->fRange.parenthesisLevel;
     } else
         return 0;
 }
 
-int SynEditStringList::bracketLevels(int Index) const
+int SynEditStringList::bracketLevels(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index>=0 && Index < mList.size()) {
         return mList[Index]->fRange.bracketLevel;
     } else
         return 0;
 }
 
-int SynEditStringList::braceLevels(int Index) const
+int SynEditStringList::braceLevels(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index>=0 && Index < mList.size()) {
         return mList[Index]->fRange.braceLevel;
     } else
@@ -62,6 +66,7 @@ int SynEditStringList::braceLevels(int Index) const
 
 int SynEditStringList::lineColumns(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index>=0 && Index < mList.size()) {
         if (mList[Index]->fColumns == -1) {
             return calculateLineColumns(Index);
@@ -71,16 +76,18 @@ int SynEditStringList::lineColumns(int Index)
         return 0;
 }
 
-int SynEditStringList::leftBraces(int Index) const
+int SynEditStringList::leftBraces(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index>=0 && Index < mList.size()) {
         return mList[Index]->fLeftBraces;
     } else
         return 0;
 }
 
-int SynEditStringList::rightBraces(int Index) const
+int SynEditStringList::rightBraces(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index>=0 && Index < mList.size()) {
         return mList[Index]->fRightBraces;
     } else
@@ -88,6 +95,7 @@ int SynEditStringList::rightBraces(int Index) const
 }
 
 int SynEditStringList::lengthOfLongestLine() {
+    QMutexLocker locker(&mMutex);
     if (mIndexOfLongestLine < 0) {
         int MaxLen = -1;
         mIndexOfLongestLine = -1;
@@ -120,8 +128,9 @@ QString SynEditStringList::lineBreak() const
     return "\n";
 }
 
-const SynRangeState& SynEditStringList::ranges(int Index) const
+const SynRangeState& SynEditStringList::ranges(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index>=0 && Index < mList.size()) {
         return mList[Index]->fRange;
     } else {
@@ -130,7 +139,7 @@ const SynRangeState& SynEditStringList::ranges(int Index) const
     return {0};
 }
 
-void SynEditStringList::InsertItem(int Index, const QString &s)
+void SynEditStringList::insertItem(int Index, const QString &s)
 {
     beginUpdate();
     PSynEditStringRec line = std::make_shared<SynEditStringRec>();
@@ -150,23 +159,21 @@ void SynEditStringList::addItem(const QString &s)
     endUpdate();
 }
 
-ConvertTabsProcEx SynEditStringList::getConvertTabsProc() const
-{
-    return mConvertTabsProc;
-}
-
-bool SynEditStringList::getAppendNewLineAtEOF() const
+bool SynEditStringList::getAppendNewLineAtEOF()
 {
+    QMutexLocker locker(&mMutex);
     return mAppendNewLineAtEOF;
 }
 
 void SynEditStringList::setAppendNewLineAtEOF(bool appendNewLineAtEOF)
 {
+    QMutexLocker locker(&mMutex);
     mAppendNewLineAtEOF = appendNewLineAtEOF;
 }
 
 void SynEditStringList::setRange(int Index, const SynRangeState& ARange, int ALeftBraces, int ARightBraces)
 {
+    QMutexLocker locker(&mMutex);
     if (Index<0 || Index>=mList.count()) {
         ListIndexOutOfBounds(Index);
     }
@@ -177,44 +184,50 @@ void SynEditStringList::setRange(int Index, const SynRangeState& ARange, int ALe
     endUpdate();
 }
 
-QString SynEditStringList::getString(int Index) const
+QString SynEditStringList::getString(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index<0 || Index>=mList.count()) {
         return QString();
     }
     return mList[Index]->fString;
 }
 
-int SynEditStringList::count() const
+int SynEditStringList::count()
 {
+    QMutexLocker locker(&mMutex);
     return mList.count();
 }
 
-void *SynEditStringList::getObject(int Index) const
+void *SynEditStringList::getObject(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if (Index<0 || Index>=mList.count()) {
         return nullptr;
     }
     return mList[Index]->fObject;
 }
 
-QString SynEditStringList::text() const
+QString SynEditStringList::text()
 {
+    QMutexLocker locker(&mMutex);
     return getTextStr();
 }
 
 void SynEditStringList::setText(const QString &text)
 {
-    PutTextStr(text);
+    QMutexLocker locker(&mMutex);
+    putTextStr(text);
 }
 
 void SynEditStringList::setContents(const QStringList &text)
 {
+    QMutexLocker locker(&mMutex);
     beginUpdate();
     auto action = finally([this]{
         endUpdate();
     });
-    clear();
+    internalClear();
     if (text.count() > 0) {
         mIndexOfLongestLine = -1;
         int FirstAdded = mList.count();
@@ -226,8 +239,9 @@ void SynEditStringList::setContents(const QStringList &text)
     }
 }
 
-QStringList SynEditStringList::contents() const
+QStringList SynEditStringList::contents()
 {
+    QMutexLocker locker(&mMutex);
     QStringList Result;
     SynEditStringRecList list = mList;
     foreach (const PSynEditStringRec& line, list) {
@@ -239,7 +253,7 @@ QStringList SynEditStringList::contents() const
 void SynEditStringList::beginUpdate()
 {
     if (mUpdateCount == 0) {
-        SetUpdateState(true);
+        setUpdateState(true);
     }
     mUpdateCount++;
 }
@@ -248,16 +262,17 @@ void SynEditStringList::endUpdate()
 {
     mUpdateCount--;
     if (mUpdateCount == 0) {
-        SetUpdateState(false);
+        setUpdateState(false);
     }
 }
 
 
 int SynEditStringList::add(const QString &s)
 {
+    QMutexLocker locker(&mMutex);
     beginUpdate();
     int Result = mList.count();
-    InsertItem(Result, s);
+    insertItem(Result, s);
     emit inserted(Result,1);
     endUpdate();
     return Result;
@@ -265,6 +280,7 @@ int SynEditStringList::add(const QString &s)
 
 void SynEditStringList::addStrings(const QStringList &Strings)
 {
+    QMutexLocker locker(&mMutex);
     if (Strings.count() > 0) {
         mIndexOfLongestLine = -1;
         beginUpdate();
@@ -282,6 +298,7 @@ void SynEditStringList::addStrings(const QStringList &Strings)
 
 int SynEditStringList::getTextLength()
 {
+    QMutexLocker locker(&mMutex);
     int Result = 0;
     foreach (const PSynEditStringRec& line, mList ) {
         Result += line->fString.length();
@@ -296,18 +313,13 @@ int SynEditStringList::getTextLength()
 
 void SynEditStringList::clear()
 {
-    if (!mList.isEmpty()) {
-        beginUpdate();
-        int oldCount = mList.count();
-        mIndexOfLongestLine = -1;
-        mList.clear();
-        emit deleted(0,oldCount);
-        endUpdate();
-    }
+    QMutexLocker locker(&mMutex);
+    internalClear();
 }
 
 void SynEditStringList::deleteLines(int Index, int NumLines)
 {
+    QMutexLocker locker(&mMutex);
     if (NumLines<=0)
         return;
     if ((Index < 0) || (Index >= mList.count())) {
@@ -328,8 +340,9 @@ void SynEditStringList::deleteLines(int Index, int NumLines)
     emit deleted(Index,NumLines);
 }
 
-void SynEditStringList::Exchange(int Index1, int Index2)
+void SynEditStringList::exchange(int Index1, int Index2)
 {
+    QMutexLocker locker(&mMutex);
     if ((Index1 < 0) || (Index1 >= mList.count())) {
         ListIndexOutOfBounds(Index1);
     }
@@ -346,19 +359,21 @@ void SynEditStringList::Exchange(int Index1, int Index2)
     endUpdate();
 }
 
-void SynEditStringList::Insert(int Index, const QString &s)
+void SynEditStringList::insert(int Index, const QString &s)
 {
+    QMutexLocker locker(&mMutex);
     if ((Index < 0) || (Index > mList.count())) {
         ListIndexOutOfBounds(Index);
     }
     beginUpdate();
-    InsertItem(Index, s);
+    insertItem(Index, s);
     emit inserted(Index,1);
     endUpdate();
 }
 
 void SynEditStringList::deleteAt(int Index)
 {
+    QMutexLocker locker(&mMutex);
     if ((Index < 0) || (Index >= mList.count())) {
         ListIndexOutOfBounds(Index);
     }
@@ -385,6 +400,7 @@ QString SynEditStringList::getTextStr() const
 }
 
 void SynEditStringList::putString(int Index, const QString &s) {
+    QMutexLocker locker(&mMutex);
     if (Index == mList.count()) {
         add(s);
     } else {
@@ -402,6 +418,7 @@ void SynEditStringList::putString(int Index, const QString &s) {
 
 void SynEditStringList::putObject(int Index, void *AObject)
 {
+    QMutexLocker locker(&mMutex);
     if (Index<0 || Index>=mList.count()) {
         ListIndexOutOfBounds(Index);
     }
@@ -410,7 +427,7 @@ void SynEditStringList::putObject(int Index, void *AObject)
     endUpdate();
 }
 
-void SynEditStringList::SetUpdateState(bool Updating)
+void SynEditStringList::setUpdateState(bool Updating)
 {
     if (Updating)
         emit changing();
@@ -426,8 +443,9 @@ int SynEditStringList::calculateLineColumns(int Index)
     return line->fColumns;
 }
 
-void SynEditStringList::InsertLines(int Index, int NumLines)
+void SynEditStringList::insertLines(int Index, int NumLines)
 {
+    QMutexLocker locker(&mMutex);
     if (Index<0 || Index>mList.count()) {
         ListIndexOutOfBounds(Index);
     }
@@ -446,8 +464,9 @@ void SynEditStringList::InsertLines(int Index, int NumLines)
     emit inserted(Index,NumLines);
 }
 
-void SynEditStringList::InsertStrings(int Index, const QStringList &NewStrings)
+void SynEditStringList::insertStrings(int Index, const QStringList &NewStrings)
 {
+    QMutexLocker locker(&mMutex);
     if (Index<0 || Index>mList.count()) {
         ListIndexOutOfBounds(Index);
     }
@@ -467,19 +486,21 @@ void SynEditStringList::InsertStrings(int Index, const QStringList &NewStrings)
     emit inserted(Index,NewStrings.length());
 }
 
-void SynEditStringList::InsertText(int Index, const QString &NewText)
+void SynEditStringList::insertText(int Index, const QString &NewText)
 {
+    QMutexLocker locker(&mMutex);
     if (Index<0 || Index>=mList.count()) {
         ListIndexOutOfBounds(Index);
     }
     if (NewText.isEmpty())
         return;
     QStringList lines = TextToLines(NewText);
-    InsertStrings(Index,lines);
+    insertStrings(Index,lines);
 }
 
-void SynEditStringList::LoadFromFile(const QString& filename, const QByteArray& encoding, QByteArray& realEncoding)
+void SynEditStringList::loadFromFile(const QString& filename, const QByteArray& encoding, QByteArray& realEncoding)
 {
+    QMutexLocker locker(&mMutex);
     QFile file(filename);
     if (!file.open(QFile::ReadOnly ))
         throw FileError(tr("Can't open file '%1' for read!").arg(file.fileName()));
@@ -514,7 +535,7 @@ void SynEditStringList::LoadFromFile(const QString& filename, const QByteArray&
         } else if (line.endsWith("\r")) {
             mFileEndingType = FileEndingType::Mac;
         }
-        clear();
+        internalClear();
         while (true) {
             if (allAscii) {
                 allAscii = isTextAllAscii(line);
@@ -558,7 +579,7 @@ void SynEditStringList::LoadFromFile(const QString& filename, const QByteArray&
         textStream.setCodec(realEncoding);
     }
     QString line;
-    clear();
+    internalClear();
     while (textStream.readLineInto(&line)) {
         addItem(TrimRight(line));
     }
@@ -567,8 +588,9 @@ void SynEditStringList::LoadFromFile(const QString& filename, const QByteArray&
 
 
 
-void SynEditStringList::SaveToFile(QFile &file, const QByteArray& encoding, QByteArray& realEncoding)
+void SynEditStringList::saveToFile(QFile &file, const QByteArray& encoding, QByteArray& realEncoding)
 {
+    QMutexLocker locker(&mMutex);
     if (!file.open(QFile::WriteOnly | QFile::Truncate))
         throw FileError(tr("Can't open file '%1' for save!").arg(file.fileName()));
     if (mList.isEmpty())
@@ -611,13 +633,13 @@ void SynEditStringList::SaveToFile(QFile &file, const QByteArray& encoding, QByt
     }
 }
 
-void SynEditStringList::PutTextStr(const QString &text)
+void SynEditStringList::putTextStr(const QString &text)
 {
     beginUpdate();
     auto action = finally([this]{
         endUpdate();
     });
-    clear();
+    internalClear();
     int pos = 0;
     int start;
     while (pos < text.length()) {
@@ -638,23 +660,39 @@ void SynEditStringList::PutTextStr(const QString &text)
     }
 }
 
-FileEndingType SynEditStringList::getFileEndingType() const
+void SynEditStringList::internalClear()
 {
+    if (!mList.isEmpty()) {
+        beginUpdate();
+        int oldCount = mList.count();
+        mIndexOfLongestLine = -1;
+        mList.clear();
+        emit deleted(0,oldCount);
+        endUpdate();
+    }
+}
+
+FileEndingType SynEditStringList::getFileEndingType()
+{
+    QMutexLocker locker(&mMutex);
     return mFileEndingType;
 }
 
 void SynEditStringList::setFileEndingType(const FileEndingType &fileEndingType)
 {
+    QMutexLocker locker(&mMutex);
     mFileEndingType = fileEndingType;
 }
 
 bool SynEditStringList::empty()
 {
-    return count()==0;
+    QMutexLocker locker(&mMutex);
+    return mList.count()==0;
 }
 
 void SynEditStringList::resetColumns()
 {
+    QMutexLocker locker(&mMutex);
     mIndexOfLongestLine = -1;
     if (mList.count() > 0 ) {
         for (int i=0;i<mList.size();i++) {
@@ -665,6 +703,7 @@ void SynEditStringList::resetColumns()
 
 void SynEditStringList::invalidAllLineColumns()
 {
+    QMutexLocker locker(&mMutex);
     mIndexOfLongestLine = -1;
     for (PSynEditStringRec& line:mList) {
         line->fColumns = -1;
diff --git a/RedPandaIDE/qsynedit/TextBuffer.h b/RedPandaIDE/qsynedit/TextBuffer.h
index 7f6e6179..c607a916 100644
--- a/RedPandaIDE/qsynedit/TextBuffer.h
+++ b/RedPandaIDE/qsynedit/TextBuffer.h
@@ -3,6 +3,7 @@
 
 #include <QStringList>
 #include "highlighter/base.h"
+#include <QMutex>
 #include <QVector>
 #include <memory>
 #include "MiscProcs.h"
@@ -50,23 +51,23 @@ class SynEditStringList : public QObject
 public:
     explicit SynEditStringList(SynEdit* pEdit,QObject* parent=nullptr);
 
-    int parenthesisLevels(int Index) const;
-    int bracketLevels(int Index) const;
-    int braceLevels(int Index) const;
+    int parenthesisLevels(int Index);
+    int bracketLevels(int Index);
+    int braceLevels(int Index);
     int lineColumns(int Index);
-    int leftBraces(int Index) const;
-    int rightBraces(int Index) const;
+    int leftBraces(int Index);
+    int rightBraces(int Index);
     int lengthOfLongestLine();
     QString lineBreak() const;
-    const SynRangeState& ranges(int Index) const;
+    const SynRangeState& ranges(int Index);
     void setRange(int Index, const SynRangeState& ARange, int leftBraces, int rightBraces);
-    QString getString(int Index) const;
-    int count() const ;
-    void* getObject(int Index) const;
-    QString text() const;
+    QString getString(int Index);
+    int count();
+    void* getObject(int Index);
+    QString text();
     void setText(const QString& text);
     void setContents(const QStringList& text);
-    QStringList contents() const;
+    QStringList contents();
 
     void putString(int Index, const QString& s);
     void putObject(int Index, void * AObject);
@@ -81,20 +82,18 @@ public:
     void clear();
     void deleteAt(int Index);
     void deleteLines(int Index, int NumLines);
-    void Exchange(int Index1, int Index2);
-    void Insert(int Index, const QString& s);
-    void InsertLines(int Index, int NumLines);
-    void InsertStrings(int Index, const QStringList& NewStrings);
-    void InsertText(int Index,const QString& NewText);
-    void LoadFromFile(const QString& filename, const QByteArray& encoding, QByteArray& realEncoding);
-    void SaveToFile(QFile& file, const QByteArray& encoding, QByteArray& realEncoding);
+    void exchange(int Index1, int Index2);
+    void insert(int Index, const QString& s);
+    void insertLines(int Index, int NumLines);
+    void insertStrings(int Index, const QStringList& NewStrings);
+    void insertText(int Index,const QString& NewText);
+    void loadFromFile(const QString& filename, const QByteArray& encoding, QByteArray& realEncoding);
+    void saveToFile(QFile& file, const QByteArray& encoding, QByteArray& realEncoding);
 
-    bool getAppendNewLineAtEOF() const;
+    bool getAppendNewLineAtEOF();
     void setAppendNewLineAtEOF(bool appendNewLineAtEOF);
 
-    ConvertTabsProcEx getConvertTabsProc() const;
-
-    FileEndingType getFileEndingType() const;
+    FileEndingType getFileEndingType();
     void setFileEndingType(const FileEndingType &fileEndingType);
 
     bool empty();
@@ -112,10 +111,11 @@ signals:
     void putted(int index, int count);
 protected:
     QString getTextStr() const;
-    void SetUpdateState(bool Updating);
-    void InsertItem(int Index, const QString& s);
+    void setUpdateState(bool Updating);
+    void insertItem(int Index, const QString& s);
     void addItem(const QString& s);
-    void PutTextStr(const QString& text);
+    void putTextStr(const QString& text);
+    void internalClear();
 
 private:
     SynEditStringRecList mList;
@@ -125,9 +125,9 @@ private:
     //int mCapacity;
     FileEndingType mFileEndingType;
     bool mAppendNewLineAtEOF;
-    ConvertTabsProcEx mConvertTabsProc;
     int mIndexOfLongestLine;
     int mUpdateCount;
+    QRecursiveMutex mMutex;
 
     int calculateLineColumns(int Index);
 };
diff --git a/RedPandaIDE/thememanager.h b/RedPandaIDE/thememanager.h
index 0c843772..f2d65772 100644
--- a/RedPandaIDE/thememanager.h
+++ b/RedPandaIDE/thememanager.h
@@ -3,10 +3,6 @@
 
 #include <QObject>
 
-class AppTheme {
-    QPalette
-};
-
 class ThemeManager : public QObject
 {
     Q_OBJECT